Studies of acid mucopolysaccharide metabolism in connective tissues

Molecular size distribution analysis of human gingival proteoglycans and glycosaminoglycans in specific periodontal diseases

In order to determine the molecular-size distribution of gingival proteoglycans (PGs) and glycosaminoglycans (GAGs) both in periodontal health and disease states, gingival tissues were obtained from patients with early onset periodontitis (EOP) and adult periodontitis (AP) and also from periodontally healthy subjects. Gel filtration chromatography of gingival PGs revealed different profiles for periodontally diseased and healthy gingiva. Healthy gingiva was mainly composed of high-molecular size proteins and PGs, while diseased gingival tissue presented a decrease in high-molecular size PG forms and a shift towards low-molecular size proteins and PGs. This indicates the degradation of PG macromolecules during periodontal disease activity. Furthermore, this shift towards low-molecular size forms was more intense in EOP patients when compared to AP patients. Gel filtration of gingival GAGs also demonstrated depolymerization of GAGs, with low-molecular size GAGs being more intense in periodontally diseased gingiva, while healthy gingival GAGs profile was mainly composed of high-molecular size GAGs. Similar to the profile of gingival PGs, low-molecular size gingival GAGs were more prominent in gingival tissue from patients with EOP. These findings suggest that both PGs and GAGs, essential components of the extracellular matrix (ECM), are depolymerized during periodontal disease activity, which is more prominent in EOP. Since the basic feature of periodontal disease is matrix degradation, ECM components, more specifically PGs and GAGs, are likely to provide valuable information for a better understanding of periodontal disease activity.

Molecular size distribution of proteoglycans in human inflamed gingival tissue

Proteoglycans were extracted from human gingiva with 2 M CaCl2. The extracts were examined by gel filtration on Sephacryl S-400 in 2 M CaCl2 under dissociative conditions. The 280 nm absorbance profiles of clinically uninflamed, inflamed and severely-inflamed tissues showed that material was present with molecular weights of between 2 X 10(6) or greater, and 16,000. Proteoglycans were examined by cellulose-acetate electrophoresis with subsequent identification of the constituent glycosaminoglycans after protease digestion, and finally by chondroitinase AC digestion of the liberated glycosaminoglycans. The relative proportion of each glycosaminoglycan was calculated by scanning each cellulose-acetate sheet on an integrating densitometer. Heparan sulphate was found only in fraction I (mol. wt 2 X 10(6) or greater), together with hyaluronic acid and chondroitin-4-sulphate, these being present in all of the glycosaminoglycan-containing fractions (I-IV). Dermatan sulphate was absent from fraction I, but present in II-IV, apparently existing on the same protein core as chondroitin-4-sulphate. The relative proportions of these two glycosaminoglycans was related to molecular size, and with the degree of inflammation for a given molecular species.

Proteoglycans in human gingiva: molecular size distribution in epithelium and in connective tissue

The major extracellular, non-fibrous macromolecules in human gingiva are proteoglycans. These sulphated, uronic acid-containing macromolecules are synthesized in vitro by both gingival epithelium and its underlying connective tissue. Biochemical analyses were carried out on cultured human predominantly gingival epithelium and predominantly connective tissue in media containing appropriate radioactive precursor molecules. The proteoglycans were extracted with salt solutions of varying concentration and characterized by means of column chromatography and liquid scintillation counting. The major differences noted between the macromolecules extracted from these closely apposed regions were molecular size, and the ability or not to form large self-aggregatable macromolecules. In general, the epithelial proteoglycans are larger than connective tissue proteoglycans. Proteoglycans from gingival epithelium are able to self-aggregate to form large macromolecules with mol. wt in excess of 2 X 10(6) which are essential for the maintenance of tissue integrity.

Degradation of fetal rat cartilage in organ culture: effect of Streptomyces hyaluronidase

Degradation of cartilage matrix was studied by characterizing the size and amount of products released from cultures of fetal rat long bones into the medium. Na32SO4 was administered to pregnant rats and the fetal radii and ulnae were explanted 24 hours later and cultured in chemically defined medium. Under these conditions, 35S-activity is released from the cartilagenous ends of the explants into the culture medium gradually over 72 hours. The 35S-labeled molecules in the medium were smaller than proteoglycan monomers and larger than papain-released products when chromatographed on Sepharose 2B. The amount of 35S-activity released into the medium decreased when heat-inactivated rat serum or plasma or heparin was added to the medium. Adding proteases or hyaluronidases or freeze-thawing the tissue enhanced release of 35S-activity. Streptomyces hyaluronidase was chromatographed on CM-cellulose and Ultrogel to remove protease activity. The protease-free enzyme released 35S-labeled molecules, similar in size to proteoglycan monomers, from cartilage which was heated before culturing to inactivate endogenous enzymes. These results indicate that hyaluronidase can degrade matrix by releasing proteoglycan monomers. Other treatments released smaller 35S-labeled molecules. These findings indicate that endogenous enzymes degrade matrix proteoglycans into smaller units.