Tokyo, Japan
Tokyo, Japan

Time filter

Source Type

Feng Y.,Norwegian University of Science and Technology | Kopplin G.,Norwegian University of Science and Technology | Sato K.,Koyo Chemical Co. | Draget K.I.,Norwegian University of Science and Technology | Varum K.M.,Norwegian University of Science and Technology
Carbohydrate Polymers | Year: 2017

Alginates are polysaccharides that are widely used in relation to their ability to form gels. Recently we reported that alginates may also form gels with chitosan oligomers as crosslinkers (Khong, Aarstad, Skjåk-Bræk, Draget, & Vårum, 2013). The purpose of the present study was to characterize alginate gels crosslinked with calcium and chitosan oligomers. Using two different alginates of similar molecular weights but different chemical composition, i.e. guluronic acid content of 46 and 68%, we found that both alginates could form homogeneous gels with calcium and chitosan oligomers separately and without syneresis. Systematic combinations of calcium and chitosan oligomers as crosslinkers were tested, showing that up to 50% of the calcium could be substituted with chitosan oligomers without reduction in gel strength or increased syneresis for the alginate with the lowest guluronic acid content. Furthermore, the kinetics of the combined gels were different from pure calcium alginate gels. © 2016 Elsevier Ltd


Igarashi M.,Juntendo University | Sakamoto K.,Juntendo University | Sakamoto K.,Koyo Chemical Co. | Nagaoka I.,Juntendo University
International Journal of Molecular Medicine | Year: 2017

Glucosamine (GlcN) has been widely used to treat osteoarthritis (OA) in humans. However, the effects of GlcN on genes related to cartilage metabolism are still unknown. In the present study, to elucidate the chondroprotective action of GlcN on OA, we examined the effects of GlcN (0.1-10 mM) on the expression of the sirtuin (SIRT) genes as well as type II collagen and matrix metalloproteinases (MMPs) using a human chondrocyte cell line SW 1353. SW 1353 cells were incubated in the absence or presence of GlcN. RT-PCR analyses revealed that GlcN markedly increased the mRNA expression of type II collagen (COL2A1). By contrast, the levels of MMP-1 and MMP-9 mRNA were only slightly increased by GlcN. Furthermore, western blot analyses revealed that GlcN significantly increased the protein level of COL2A1. Importantly, GlcN enhanced the mRNA expression and protein level of SIRT1, an upstream-regulating gene of COL2A1. Moreover, a SIRT1 inhibitor suppressed GlcN-induced COL2A1 gene expression. Together these observations suggest that GlcN enhances the mRNA expression and protein level of SIRT1 and its downstream gene COL2A1 in chondrocytes, thereby possibly exhibiting chondroprotective action on OA.


Azuma K.,Tottori University | Osaki T.,Tottori University | Tsuka T.,Tottori University | Imagawa T.,Tottori University | And 3 more authors.
Marine Drugs | Year: 2011

We examined the effects of oral glucosamine hydrochloride (GlcN), N-acetyl-D-glucosamine (GlcNAc) and D-glucose (Glc) administration on plasma total free amino acid (PFAA) concentrations in dogs. The PFAA concentrations increased in the control group and the GlcNAc group at one hour after feeding, and each amino acid concentration increased. On the other hand, in the GlcN group and the Glc group PFAA concentrations decreased at one hour after feeding. A significant decrease in amino acid concentration was observed for glutamate, glycine and alanine. Our results suggest the existence of differences in PFAA dynamics after oral administration of GlcN and GlcNAc in dogs. © 2011 by the authors; licensee MDPI.


Ito I.,Tottori University | Osaki T.,Tottori University | Ifuku S.,Tottori University | Saimoto H.,Tottori University | And 7 more authors.
Carbohydrate Polymers | Year: 2014

Chitins are highly crystalline structures that are predominantly found in crustacean shells. Alpha-chitin is composed of microfibers, which are made up of nanofibrils that are 2-5 nm in diameter and 30 nm in length and embedded in a protein matrix. Crystalline nanofibrils can also be prepared by acid treatment. We verified the effect of chitin nanofibrils (NF) and nanocrystals (NC) on skin using a three-dimensional skin culture model and Franz cells. The application of NF and NC to skin improved the epithelial granular layer and increased granular density. Furthermore, NF and NC application to the skin resulted in a lower production of TGF-β compared to that of the control group. NF and NC might have protective effects to skin. Therefore, their potential use as components of skin-protective formulations merits consideration. © 2013 Elsevier Ltd. All rights reserved.


PubMed | Koyo Chemical Co. and Norwegian University of Science and Technology
Type: | Journal: Carbohydrate polymers | Year: 2016

Alginates are polysaccharides that are widely used in relation to their ability to form gels. Recently we reported that alginates may also form gels with chitosan oligomers as crosslinkers (Khong, Aarstad, Skjk-Brk, Draget, & Vrum, 2013). The purpose of the present study was to characterize alginate gels crosslinked with calcium and chitosan oligomers. Using two different alginates of similar molecular weights but different chemical composition, i.e. guluronic acid content of 46 and 68%, we found that both alginates could form homogeneous gels with calcium and chitosan oligomers separately and without syneresis. Systematic combinations of calcium and chitosan oligomers as crosslinkers were tested, showing that up to 50% of the calcium could be substituted with chitosan oligomers without reduction in gel strength or increased syneresis for the alginate with the lowest guluronic acid content. Furthermore, the kinetics of the combined gels were different from pure calcium alginate gels.


Nagaoka I.,Juntendo University | Igarashi M.,Juntendo University | Hua J.,Juntendo University | Ju Y.,Juntendo University | And 2 more authors.
Carbohydrate Polymers | Year: 2011

Glucosamine, a naturally occurring amino monosaccharide, is present in the connective and cartilage tissues as a component of glycosaminoglycans. Thus, glucosamine has been widely used to treat osteoarthritis, a joint disease characterized by cartilage degeneration, in humans. In addition, glucosamine is expected to exert an anti-inflammatory action, since glucosamine suppresses inflammatory cell activation. To further extend the anti-inflammatory actions of glucosamine, we investigated the effects of glucosamine on synovial cells, endothelial cells and intestinal epithelial cells using in vitro and in vivo systems. Firstly, glucosamine suppressed the IL-1β-induced activation of synovial cells in vitro. Furthermore, glucosamine administration repressed synovial cell hyperplasia, cartilage destruction and inflammatory cell infiltration in rat adjuvant arthritis. Secondary, glucosamine suppressed the TNF-α-induced activation of intestinal epithelial cell HT-29 in vitro. In addition, glucosamine administration improved the clinical symptoms, and colonic inflammation and tissue injury in dextran sulfate sodium-induced colitis in rats. Finally, glucosamine suppressed the TNF-α-induced activation of endothelial cells in vitro. Moreover, glucosamine administration repressed the formation of atherosclerotic lesion and infiltration of inflammatory cells into the lesion in spontaneously hyperlipidemic mice B6 KOR Aposhl. Together these observations support the idea that glucosamine can function as not only a chondroprotective agent but also an anti-inflammatory molecule in the body. © 2011 Elsevier Ltd. All rights reserved.


Nagaoka I.,Juntendo University | Igarashi M.,Juntendo University | Sakamoto K.,Koyo Chemical Co.
Advances in Food and Nutrition Research | Year: 2012

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. © 2012 Elsevier Inc.


Someya A.,Juntendo University | Ikegami T.,Juntendo University | Sakamoto K.,Koyo Chemical Co. | Nagaoka I.,Juntendo University
PLoS ONE | Year: 2016

Osteoarthritis (OA) is one of the major joint diseases, and the synovial inflammation is involved in the pathogenesis and progression of OA. Glucosamine (GlcN) is widely used as a dietary supplement for OA, and is expected to exert the antiinflammatory action in OA. However, the detailed mechanism for the antiinflammatory action of GlcN remains poorly understood. In this study, to elucidate the molecular mechanism involved in the GlcN-medicated regulation of synovial cell activation, we comprehensively analyzed the effect of GlcN on the gene expression using a human synovial cell line MH7A by DNA microarray. The results indicated that GlcN significantly downregulates the expression of 187 genes (<1/1.5-fold) and upregulates the expression of 194 genes (≥1.5-fold) in IL-1β-stimulated MH7A cells. Interestingly, pathway analysis indicated that among the 10 pathways into which the GlcN-regulated genes are categorized, the 4 pathways are immune-related. Furthermore, GlcN suppressed the expression of proinflammatory cytokine genes (such as IL-6, IL-8, IL-24 and TNF-α genes). In addition, GlcN-mediated O-GlcNAc modification was involved in the downregulation of TNF-α and IL-8 genes but not IL-6 and IL-24 genes, based on the effects of alloxan, an O-GlcNAc transferase inhibitor. Thus, GlcN likely exerts an antiinflammatroy action in OA by suppressing the expression of proinflammatory cytokine genes in synovial MH7A cells by OGlcNAc modification-dependent and -independent mechanisms. Copyright: © 2016 Someya et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


Trademark
Koyo Chemical Co. | Date: 2010-06-01

Chemicals for use in the manufacture of nutritional supplements, namely, glucosamine; glucosamine hydrochlorides and glucosamine sulphates.


Trademark
Koyo Chemical Co. | Date: 2010-06-15

Chemicals for use in the manufacture of nutritional supplements, namely, glucosamine; glucosamine hydrochlorides and glucosamine sulphates.

Loading Koyo Chemical Co. collaborators
Loading Koyo Chemical Co. collaborators