Degradation of glycosaminoglycans by reactive oxygen species derived from stimulated polymorphonuclear leukocytes

Abstract

The effect of reactive oxygen species (ROS), generated by in vitro stimulation of isolated PMN upon the main GAG components of mineralised and non-mineralised connective tissues was investigated. PMN were isolated from whole blood and the production of the ROS superoxide (O2.-) and hydroxyl radicals (.OH) was stimulated by the addition of phorbol myristyl acetate (PMA) and PMA/FeCl3-EDTA chelate respectively and their production assessed over a 24 h period. The glycosaminoglycans (GAG), hyaluronan, chondroitin 4-sulphate and dermatan sulphate, were exposed to the ROS fluxes, incubated at 37 degrees C for 1 h and 24 h. GAG fragmentation was examined by gel exclusion chromatography and modification to hexuronic acid and hexosamine residues determined. Stimulation of PMN with PMA resulted in a burst of O2.- production for 1 h, which was sustained at a reduced level for 24 h. Fragmentation of GAG was observed for all GAG examined. Modification to the GAG was evident, with hyaluronan being more susceptible to loss of GAG residues than sulphated GAG. Modification of sugar residues increased with the incubation time and loss of the hexuronic acid residues was greater than loss of hexosamine residues. Addition of FeCl3-EDTA chelate, which led to the generation of .OH and was sustained over the 24 h period, demonstrated similar trends of GAG modification although increased degradation and loss of hexosamine and hexuronic acid were observed. GAG chains are constituents of PGs and their modification is likely to affect the function of these macromolecules and be of importance in considering the pathogenesis of inflammatory diseases, including periodontal diseases.

Effect of Sodium Ascorbate on Dentin Bonding After Two Bleaching Techniques

“…Sulfur is a component of proteoglycans (chondroitin sulfate and keratan sulfate), and changes in their levels indicate damage to the organic dentin matrix. [38][39][40] These changes in proteoglycans might interfere in the maintenance of interfibrillar spaces, 41 which may have compromised diffusion of the adhesive into the collagen network, potentially reducing the bond strength in this current study. 42,43 The specimens from group C (Figure 3) presented a thick hybrid layer þ resin tags and also high microtensile bond strength values.…”

Damage of the Endothelial Glycocalyx in Dialysis Patients

“…[29][30][31] In vitro studies have shown that inflammatory cytokines, particularly IL-1, IL-6, and TNF-a, as well as reactive oxygen species are involved in the degradation of HA. [32][33][34] High serum levels of HA have been reported in CKD [35][36][37] and seem to be a risk predictor of poor survival in dialysis. 38 However, the mechanisms underlying the increased levels have not been fully explained.…”

Increased salivary level of 8-hydroxydeoxyguanosine is a marker of premature oxidative mitochondrial DNA damage in gingival tissue of patients with periodontitis

“…Several lines of evidence implicate polymorphonuclear cells (PMNs) as the primary mediators of the host response against periodontopathic bacteria (Miller et al 1984). A study carried out by Moseley et al (Moseley et al 1997) demonstrates that PMNs produce a range of antimicrobial factors, including ROS, during the phagocytosis of periodontopathic bacteria. ROS have recently been reviewed in the pathogenesis of periodontitis (Canakci et al 2005).…”