Hyaluronan oxidation

Keywords Glycosaminoglycans, hyaluronan biosynthesis, hyaluronan catabolism, hyaluronan oxidative degradation, inflammation, inflammatory mediators, regenerative medicine... 

Dr. Soltes has been employed for over 30 years at Academic Research Institutes in Bratislava, Slovakia. His research related to the polysaccharides, which started over two decades ago, resulted in patenting a novel approach "Clathrate complexes formed by hyaluronic acid derivatives and use thereof as pharmaceuticals". His current research interests are focused on the studies of hyaluronan oxidative damage and the regulation of this process. Dr. Soltes is the sole distinguished representative of Slovakia in the International Society for Hyaluronan Sciences. In 2007 he was named Scientist of the Year of the Slovak Republic. 

Weng, L., Pan, H. Chen, W. 2008, Self-crosslinkable hydrogels composed of partially oxidized hyaluronan and gelatin in vitro and in vivo responses . Journal of... 

Scheme 23.5 Enzymatic synthesis of hyaluronan hydrogel via an oxidative coupling.

MuzzareUi, RAA., MuzzareUi, C., Cosani, A., Terbojevich, M. 1999. 6-Oxychitins, novel hyaluronan-like polysaccharides obtained by regioselective oxidation of chitins. Carbohydrate Polymers 39 361-367. 

Some chemical or enzymic methods are recognized to allow the specific oxidation of primary hydroxyls in the C-6 position. The TEMPO method applied to polysaccharides was used to oxidize the A7-acetylglucoamine imit in hyaluronan (20) galactose oxidase was used to modify the galactose side groups in galac-tomannan (21,22). 

Oxidized hyaluronic acid was coupled with chitosan to form porous scaffolds after freeze drying. The proportion of porosity of the freeze-dried chitosan-hyaluronic acid dialdehyde composite (CHDA) gels enhanced with augmentation in oxidation. Fibroblast cells seeded onto CHDA porous scaffold adhered, proliferated and offered extracellular matrix components on the scaffold [99]. Chondrocytes encapsulated in CHDA gels retained their viability and specific phenotypic features. The gel material is therefore projected as a scaffold and encapsulated material for tissue engineering applications. Films of hyaluronan (HA) and a phosphoryl choline-modified chitosan (PC-CH) were constructed by the electrolyte multilayer (PEM)... 

Parsons BJ, Al-Assaf S, Navaratnam S, Phillips GO. Comparison of the reactivity of different reactive oxidative species (ROS) towards hyaluronan. In Kennedy JF, Phillips GO, Williams PA, HascaU VC, editors. Hyaluronan, 1. Abington, GB Woodhead Publishing Ltd 2002. p. 141-50. 

Hyaluronan Degradation under Free-radical Oxidation Stress Action and Healing 109... 

Oxidation stress is unbalanced between prooxidants and natural antioxidants in body that lead to several diseases such as rheumatoid. Hyaluronic acid (HA), is a high molecular weight biopolysacharide, is found in the extracellular matrix of soft connective tissues and is particularly concentrated in synovial fluid (SF). Half-live time of Hyaluronan in SF is approximately 12 hrs in normal conditions. This process is accelerated under normal oxidation stress that generates troubles in human joints. 

This chapter describe oxidation stress-source and effects-Hyaluronan origin, properties and functions, and finally thiol compounds as antioxidants preventing HA degradations under conditions of oxidation stress. 

FIGURE 9 Evaluation of antioxidative effects of N-acetyl-l-cysteine against high-molar-mass hyaluronan degradation in vitro induced by Weissbeiger s oxidative system. Reference sample (black) 1 pM Cu (11) ions plus 100 pM ascorbic acid nil thiol concentration. N-Acetyl-1-cysteine addition at the onset of the reaction (a) and after 1 h (b) (25,50,100 pM). (Hrabarova E,etal2012). 

Hrabarova E, Katarina Valachova, Jozef Rychly, Peter Rapta, Vlasta Sasinkova, Marta Mahkova, Ladislav Soltes. High-molar-mass hyaluronan d radation by Weissbeiger s system Pro- and anti-oxidative effects of some thiol compounds. Polymer Degradation and Stability 94 (2009) 1867-1875. 

HrabdrovdE., ValachovdK., Juranek ., Soltes L. Free-radical degradation of high-molar-mass hyaluronan induced by ascorbate plus cupric ions. Anti-oxidative properties of the PieSt any-spa curative waters from healing peloid and maturation pool. In Kinetics, Catalysis and Mechanism of Chemical Reactions G. E. Zaikov (eds). Nova Science Publishers,New York, 2011 pp. 29-36. 

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