Extracellular matrix hyaluronic acid

Hyaluronic acid is made from glucuronic acid and N-acetylglucosamine It may have a molecular weight as high as 10 million and is much larger than the other GAGs. In the extracellular matrix, hyaluronic... 

Hyaluronic acid is a linear polysaccharide found in the highest concentrations in soft connective tissues where it fills an important structural role in the organization of the extracellular matrix (23,24). It has been used in ophthalmic preparations to enhance ocular absorption of timolol, a beta blocker used for the treatment of glaucoma (25), and in a viscoelastic tear formulation for conjunctivitis (26). The covalent binding of adriamycin and daunomycin to sodium hy-aluronate to produce water-soluble conjugates was recently reported (27). 

ECM, extracellular matrix HA, hyaluronic acid CS, chondroitin sulfate KS I, keratan sulfate I DS, dermatan sulfate HS, heparan sulfate. 

CD44 Known to be z leucocyte adhesion molecule also known as hyaluronic acid cell adhesion molecule (H-CAM), Hermes antigen, extracellular matrix receptor III (ECMIII) present on polymorphonuclear leucocytes CI)45 Known to be z pan leucocyte marker... 

PMNs also produce oxygen-derived free radicals when exposed in vitro to chrysotile or crocidolite. The highly reactive superoxides could injure other cells or attack extracellular matrix molecules. Hyaluronic acid (part of the mucopolysaccharide molecule) is a particularly vulnerable matrix species, but the specific reaction mechanisms have not been elucidated. 

Hyaluronate (a glycosamino-glycan) Hetero- acidic 4)GlcA(/31—>3) GlcNAc(j31 Up to 100,000 Structural in vertebrates, extracellular matrix of skin and connective tissue viscosity and lubrication in joints... 

Proteoglycan aggregates are typically found in the extracellular matrix of connective tissue. The noncovalent attachment of each proteoglycan to hyaluronic acid via the core protein is mediated by two linker proteins (not shown). Proteoglycans interact with numerous fibrous proteins in the extracellular matrix such as collagen, elastin, and fibronectin (a glycoprotein involved in cell adhesion). 

Hyaluronan is continuously synthesized and secreted by fibroblasts, keratino-cytes, chondrocytes and other specialized cells in the extracellular matrix (ECMs) throughout the body. It is synthesized by HA synthase (see also Chapter 9) at the inner face of the plasma membrane [98]. The level of HA synthesis is very high in skin and cartilage [99]. Hyaluronic acid is not one of the major components of the ECMs of the connective tissues, but it is found in various locations such as synovial fluid, vitreous humor, and umbilical cords [100]. Its biological functions include the maintenance of mechanical properties such as swelling in connective tissues and control of tissue hydration, providing lubricating properties in synovial fluid and heart valves. 

Inflammatory processes in the liver increase production of cytokines, chemokines, and signaling molecules, which activate the stellate cells to produce a complex extracellular glycoprotein matrix (i.e., the development of fibrosis). The matrix formed includes collagen, elastin, fibronectin, and laminin. Several noninvasive tests can be used as nonspecific indicators of fibrosis, but these have not been widely applied in laboratory animals. These tests include the collagen markers type III procollagen, YKL-40, and hyaluronic acid however, these tests have not been widely evaluated in laboratory animals (Cho and Lee 1998 Tran et al. 2000 Ding et al. 2001 Mardini and Record 2005). 

Hyaluronidase is involved in bacterial and fungal infections because of virulence factors evoked by tissue degradation and mediates host-pathogen interactions [47]. Since hyaluronic acid (HA) is a major component of the extracellular matrix involved in joint lubrication, a sensitive hyaluronidase assay is important. Current hyaluronidase assays rely on turbidimetric techniques that require high levels of the enz3Tne and are relatively inaccurate [47]. HA was previously shown to bind cyanines [48,49[. The detection scheme designed for CMA, CMC, and amylase enzyme described earlier was also applicable to HA and hyaluronidase activity [19]. Scaffold Destruction ... 

Figure 3 Proposed interactions between mechanical strain, proteoglycans (PGs), and transforming growth factor (TGF)-P in the extracellular environment of the airway wall. Excessive mechanical strain stimulates fibroblasts to increase PG secretion and deposition. The altered viscoelastic properties of the matrix subsequently modulate transmission of the mechanical signal to the airway structural cell and, thereby, protect the cell from mechanical strain-induced injury. In addition, increases in decorin may result in enhanced binding of TGF-P and thereby influence the effects of this cytokine on the fibroblast. Finally, changes in small PGs, such as decorin and lumican, may affect formation of collagen fibrils. CS, chondroitin sulfate HA, hyaluronic acid.

Dillon PW, Keefer K, Blackburn JH, Houghton PE, Krummel TM. The extracellular matrix of the fetal wound hyaluronic acid controls lymphocyte adhesion. J Surg Res 1994 57 170-173. 

---