Extracellular space and extracellular matrix
The extracellular space refers to the space outside the cells and is occupied by fluid and various metabolites, ions, proteins, lipids and other biomolecules framing the structure of the respective tissue like the extracellular matrix, affecting cellular function such as extracellular vesicles, cytokines, chemokines, hormones and growth factors, or dealing with tasks outside the cells such as various enzymes or proteases.
The extracellular matrix consists of a three-dimensional macromolecular non-cellular framework built of different matrix molecules providing different functions such as structural support to the surrounding cells and separation of different tissues as well as control of intercellular communication, signal transduction and regulatory effect on cellular processes such as growth, adhesion, migration, apoptosis or differentiation. Subtypes include the interstitial matrix and the pericellular matrix as the basement membrane .
Its composition varies among different tissue types and includes the following components :
- glycosaminoglycans (GAGs) and proteoglycans
- collagen
- elastin
- fibronectin
- laminin
- and other glycoproteins
Various cell types contribute to the development and the constant remodeling of the extracellular matrix e.g. fibroblasts, osteoblasts or chondrocytes .
Clinical importance
The extracellular matrix has been attributed to a role in regrowth and tissue or wounds healing, which is of therapeutic significance .
Changes in extent and composition of the extracellular space and the extracellular matrix can be observed in different physiologic and pathologic processes , impact diffusion and the distribution of most contrast agents. The extent of the extracellular space can be assessed by measures of extracellular volume quantification.
See also
