Table 1: Functions of native hyaluronan and its fragments during tissue homeostasis and inflammation.

HMW hyaluronan LMW hyaluronan

Contributes to the protective role of the glycocalyx, acts as a lubricantInduces chemokine and cytokine secretion by infiltrating, mesothelial, renal tubular epithelial and endothelial cells
Transportation and distribution of plasma proteinsInduces phosphorylation of signaling pathways, for example, MAPK
Contributes to water balance and regulation of tissue hydrationInduces cell migration, for example, tumor cells
Contributes to tissue integrity and maintenance of epithelial cell phenotypeInduces cell proliferation in chondrocytes, endothelial cells, and fibroblasts
Protects against tissue damage by scavenging free radicalsActivates NFκB
Protects against apoptosisInduces nitric oxide synthase
AntiangiogenicPromotes angiogenesis
Inhibits phagocytosis by monocytes and macrophagesIncreases matrix protein synthesis, for example, collagen type I
Anti-inflammatory, can inhibit activation of inflammatory cellsIncreases transcription of matrix metalloproteinases
Promotes cell quiescenceSuppresses cell death and apoptosis in cell culture
Immunosuppressive (prevents ligand binding to surface receptors)Induces heat-shock protein expression

LMW hyaluronan: ranges from 4 to 40 saccharide units.