IMPACT OF TRANSITION METALS IN THE FREE-RADICAL DEGRADATION OF HYALURONAN BIOPOLYMERS

Due to their electronic configuration, transition metals readily participate in reductive-oxidative processes, thus contributing to the formation of free radicals, lipid peroxidation and oxidative DNA damage. In living (biogenic) organisms, there exist eight naturally-occurring transition metals, essential for the control of various metabolic and signaling pathways. In this overview, the role of these metals in physiological and pathophysiological processes is described, and their participation in the initiation and propagation of radical chain reactions - leading to oxidative stress and damage to the tissues - is critically assessed. Special attention is given to the involvement of biogenic transition metals in the catabolism of hyaluronan in the joint, where the oxidative degradation of this high-molar-mass glycosaminoglycan may lead to an impaired lubricating function of the synovial fluid, resulting in arthritic and inflammatory conditions.