Extracellular matrix collagen

A number of companies supply dishes and TC trays precoated with extracellular matrix collagen, or gelatin (e.g. International Biotechnologies Ltd., and Bibby Science Products Ltd.). This promotes attachment and flattening and is essential for growth of cells such as the F9 teratocarcinoma cells. 

Scaffolds can be made from natural or synthetic materials. Such materials fall under the category of biomaterials. A biomaterial can be considered a single element or compound, which is a composite or mixture of elements, and is synthesized or derived to be used in the body to preserve, restore, or augment the structure or function of the body. Examples of natural materials for scaffold construction are extracellular matrix, collagen, fibrin, and polysaccharides (e.g., chitosan or glycosaminoglycans). Natural materials, unless they are obtained from the patient who receives the neo-organ implant, will cause an immunogenic response. This is not always the case with synthetic materials. 

Fig. 3.1 Composition of the connective tissue extracellular matrix. Collagen fibers, maroon Elastic fibers, green Hyaluronan-proteoglycan matrix, gray. Fibroblasts, a macrophage, a mast cell, and a capillary containing a red blood cell are also shown (Modified from Fig. 19-34 in The Molecular Biology of the Cell. B. Alberts et al., 4th Ed. 2002. Garland Science, Taylor Francis Group, NY)...

As the main component of the extracellular matrix, collagen is the main stmctural protein in the human body and mammals. The most common collagen is the fibrillar type I, which is the main organic component in skin, bone, tendon, and inner organs. 

Kielty, C.M., Hopkinson, 1., Grant, M.E. Collagen structure, assembly and organization in the extracellular matrix. In Connective Tissue and its Heritable Disorders Wiley-Liss, Chichester, pp. 103-147, 1993. 

Molecules released by exocytosis fall into three categories (1) They can attach to the cell surface and become peripheral proteins, eg, antigens. (2) They can become part of the extracellular matrix, eg, collagen and glycosaminoglycans. (3) They can enter extracellular fluid and signal other cells. Insulin, parathyroid hormone, and the catecholamines are all packaged in gran-... 

The same ceUs that secrete collagen also secrete fi-bronectin, a large glycoprotein present on cell surfaces, in the extracellular matrix, and in blood (see below). Fi-bronectin binds to aggregating precollagen fibers and alters the kinetics of fiber formation in the pericellular matrix. Associated with fibronectin and procollagen in... 

Integrins themselves are found on nearly all cells and mediate several physiological responses, such as cell-cell and cell-matrix interactions. Three families of integrins, each family with a common beta subunit in combination with distinct alpha subunits, have been recognized. The beta 1 family, also called very late lymphocyte-activation antigen or VLA, has receptors mediating extracellular matrix interactions with molecules such as collagen, laminin, and fibronectin. Naturally, platelets contain many of the receptors of the beta 1 family. 

Therefore it is of interest to determine whether carotenoids can modulate the turnover of the extracellular matrix by the RPE by affecting the expression of MMPs, elastin, and/or collagen. Cultured RPE cells are a suitable model for such investigations. 

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