title: Biological activities of glucosamine and its related substances.
abstract: Glucosamine (GlcN) has been widely used to treat osteoarthritis (OA) in humans. We revealed that among GlcN-derivatives (GlcN and N-acetyl-d-glucosamine) and uronic acids (d-glucuronic acid and d-galacturonic acid), only GlcN induces the production of hyaluronic acid (HA) by synovial cells and chondrocytes, and the production level is much higher (>10-fold) in synovial cells compared with chondrocytes. Moreover, GlcN increases the expression of HA-synthesizing enzymes (HAS) in synovial cells and chondrocytes. These observations indicate that GlcN likely exhibits the chondroprotective action on OA by modulating the expression of HAS and inducing the production of HA (a major component of glycosaminoglycans contained in the synovial fluid) especially by synovial cells. The pathological change of subchondral bone is implicated in the initiation and progression of cartilage damage in OA. Thus, we further determined the effect of GlcN on the bone metabolism (osteoblastic cell differentiation). The results indicated that GlcN increases the mineralization of mature osteoblasts and the expression of middle and late stage markers (osteopontin and osteocalcin, respectively) during osteoblastic differentiation, and reduces the expression of receptor activator of NF-κB ligand (RANKL), a differentiation and activation factor for osteoclasts. These observations likely suggest that GlcN has a potential to induce the osteoblastic cell differentiation and suppress the osteoclastic cell differentiation, thereby increasing bone matrix deposition and decreasing bone resorption to modulate bone metabolism in OA.
authors.affiliation: Department of Host Defense and Biochemical Research, Juntendo University, Graduate School of Medicine, Tokyo, Japan. nagaokai@juntendo.ac.jp
authors.forename: Isao
authors.initials: I
authors.lastname: Nagaoka
authors.forename: Mamoru
authors.initials: M
authors.lastname: Igarashi
authors.forename: Koji
authors.initials: K
authors.lastname: Sakamoto
mesh_terms: D000117:Acetylglucosamine / Q000096:biosynthesis / Q000378:metabolism / Q000627:therapeutic use; D000818:Animals; D059001:Aquatic Organisms / Q000378:metabolism; D050071:Bone Density Conservation Agents / Q000378:metabolism / Q000627:therapeutic use; D002113:Calcification, Physiologic; D019902:Chondrocytes / Q000378:metabolism; D019587:Dietary Supplements; D005944:Glucosamine / Q000031:analogs & derivatives / Q000096:biosynthesis / Q000378:metabolism* / Q000627:therapeutic use*; D020723:Glucuronic Acid / Q000096:biosynthesis / Q000378:metabolism / Q000627:therapeutic use; D006603:Hexuronic Acids / Q000378:metabolism / Q000627:therapeutic use; D006801:Humans; D006820:Hyaluronic Acid / Q000378:metabolism; D010003:Osteoarthritis / Q000178:diet therapy* / Q000378:metabolism / Q000517:prevention & control; D010006:Osteoblasts / Q000378:metabolism; D010010:Osteoclasts / Q000378:metabolism; D013583:Synovial Membrane / Q000378:metabolism
chemical_list: D050071:Bone Density Conservation Agents; D006603:Hexuronic Acids; C007819:galacturonic acid; D020723:Glucuronic Acid; D006820:Hyaluronic Acid; D005944:Glucosamine; D000117:Acetylglucosamine