Isolation and some structure analyses of a copolymeric chondroitin sulfate-dermatan sulfate proteoglycan from post-burn, human hypertrophic scar

An accumulation of proteoglycans in scarred fascia

A little is known about proteoglycan (PG) changes, occuring in the course of scarring of tissues another than skin. The aim of present study was biochemical characterization of glycosaminoglycans (GAGs) and proteoglycans (PGs) of normal and scarred fascia. Samples of normal fascia lata were taken at autopsy from 23 individuals and samples of scarred fascia lata were removed from 23 patients at reoperations for femoral fracture. The obtained tissues were divided into two samples: first of them was submitted to GAG isolation and the second one to PG isolation. GAGs were extracted by extensive papain digestion followed by the fractionation using cetylpyridinium chloride. In order to qualitative and quantitative characterization GAGs were submitted to electrophoresis on cellulose acetate before and after treatment with enzymes, specifically depolymerizing some kinds of GAGs. PGs were extracted using 4 M guanidine HCl followed by purification by forming complexes with Alcian blue. PGs were submitted to gel permeation chromatography on Sepharose 4B. In order to obtain core proteins PGs were depolymerized with chondroitinase ABC. The purified PGs and their core proteins were separated with sodium dodecyl sulphate/polyacrylamide gel electrophoresis (SDS/PAGE). It was found that total GAGs content was significantly elevated in scarred fascia. Both types of fascia contained chondroitin-, dermatan- and heparan sulphates and hyaluronic acid. Dermatan sulphates (DS) were the predominant GAGs of normal and scarred fascia. The contents of all GAG types were increased in scarred fascia. Both types of fascia contained two kinds of dermatan sulphate proteoglycans (DSPGs); first being similar to biglycan and the second one similar to decorin, as it was judged by molecular weight of their native molecules and core proteins as well as type of GAG components. Densitometric analysis showed that decorin is a predominant DSPG in both fascia types, but in scarred tissue the ratio of biglycan to decorin is considerably higher. Moreover, in scarred fascia a large chondroitin sulphate proteoglycan (CSPG) was also observed. The obtained results have shown that the scar formation is accompanied by quantitative and qualitative alterations in GAGs/PGs resembling those observed in hypertrophic skin scars. The biochemical modification of the scarred fascia lata may partly explain the clinically manifested damage to biomechanical properties of this tissue.

Immunohistochemical localization of the proteoglycans decorin, biglycan and versican and transforming growth factor-beta in human post-burn hypertrophic and mature scars

The distributions of the small proteoglycans, decorin and biglycan and the large proteoglycan, versican, in normal skin and post-burn hypertrophic and mature scars, were compared using monoclonal and polyclonal antibodies to the core proteins. Biglycan and versican were virtually undetectable in normal dermis but readily seen in hypertrophic scars. Staining for decorin was strong throughout the dermis in normal skin but restricted to the deep dermis and a narrow zone under the epidermis in hypertrophic scar--areas which did not stain for versican. Decorin was absent or reduced in the nodules in these specimens. In mature post-burn scars, staining for all three proteoglycans demonstrated an intensity that was intermediate between that in normal dermis and that in the nodules of the hypertrophic scars. Transforming growth factor-beta was present in the nodules of hypertrophic scars but the deep dermis of these specimens stained most intensely for this cytokine which was also found in the dermis of mature scars but was not detectable in normal dermis. The apparent co-distribution of decorin and transforming growth factor-beta suggests that this proteoglycan may play an active role in the resolution of the scars. Changes in proteoglycan type and distribution could possibly account, at least in part, for the derangement of collagen and the altered physical properties of hypertrophic scar tissue.

Proteoglycans in human burn hypertrophic scar from a patient with Ehlers-Danlos syndrome

Proteoglycans (PGs) from human burn hypertrophic scar of a patient with Ehlers-Danlos syndrome were extracted with 4M guanidinium chloride and purified by DEAE-cellulose chromatography. Differential ethanol precipitation of the PG fraction obtained after ion-exchange chromatography yielded two low mol.-wt. PGs, on rich in glucuronic acid (PGGLCA; Mr 66 kDa) and the other rich in iduronic acid (PGIDOA; Mr 48 kDa). In PGGLCA, 84% of the glycosaminoglycan chains are composed of GlcA----GalNAc(SO4) units, whereas in PGIDOA, the chains contain 95% IdoA----GalNAc(SO4) disaccharide units. Upon treatment with testicular hyaluronidase, the PGs gave different-sized oligosaccharides. Chondroitinase ABC digestion of PGGLCA or PGIDOA gave a single protein core (Mr approximately 20 kDa). The presence of glucosamine and sialic acid in PGGLCA and PGIDOA suggests that both contain N-linked oligosaccharides.

Purification and characterization of iduronic acid-rich and glucuronic acid-rich proteoglycans implicated in human post-burn keloid scar

Small proteoglycans (PGs), extracted from human keloid scar tissue with 4M guanidinium chloride and fractionated by DEAE-cellulose chromatography, were separated by ethanol precipitation into one L-iduronic acid-rich and one D-glucuronic acid-rich fraction. The size of the L-iduronic acid-rich PG was 102 kDa with a 27 kDa glycosaminoglycan chain, that of the D-glucuronic acid-rich PG was 90 kDa with a 26 kDa glycosaminoglycan chain, and the protein core of both PGs was 14.5 kDa. The two PGs carried sulfate groups mostly attached at C-4 of the 2-amino-2-deoxy-D-galactose units. The N-terminal amino acid sequence of both was similar to human bone PGII (decorin), normal and hypertrophic scar, and human dermal tissue PG.