Biomedical Engineering Reference
In-Depth Information
Figure 9.1. Chemical structure of hyaluronic acid and its functional
groups; 6 -OH of N -acetyl D-glucose amine and -COOH of D-glucuronic
acid. 16
some endothelial cells and osteoarthritis, such as leukocytes, chon-
drocytes, and synoviocytes. 14 The wide distribution of these recep-
tors on the membrane of many cell types accounts for its diverse
and specific biological effects. As an example, the binding of HA to
two hyalhedrisn such as RHAMM and CD44 has been reported to
trigger intracellular signal events such as cytokine release and pro-
tein phosphorylation cascades, as well as stimulation of cell cycle
proteins, e.g. in leukocytes. The receptor interaction of HA through
CD44stimulatestransductionandothercell-signalingpathwaysthat
modulate cell functions, such as its adhesion, migration, prolifera-
tion, and endocytosis as well as HA degradation and uptake. 15 The
interaction through RHAMM has been known to regulate cellular
responses to growth factors and plays a role in cell migration in
fibroblasts.HAdegradesbytheactionsofreactiveoxygenintermedi-
ates and three types of enzymes, hyaluronidase, β -D-glucuronidase,
and β - N -acetyl-hexoaminidase, from macrophases, fibroblasts and
endothelialcells.Inadditiontotheseenzymaticdegradation,HAhas
been known to contribute on pathological processes such as arthri-
tis, wound-healing responses, vascular diseases and hemocompati-
bility by its concentration and molecular weight distribution, thus
being employed as diagnosticmarkers for disease.
These chemical and biological properties of HA led to a recog-
nition of its applications in tissue engineering scaffolds, leading to
thenecessityofthedevelopmentmethodsforchemicalmodification
 
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