Failure of Proteoglycans to Form Aggregates in Morphologically Normal Aged Human Hip Cartilage

Abstract

The macromolecular organization of proteoglycans in morphologically and histochemically normal hip cartilage from aged humans has been studied. In contrast to findings in articular and nonarticular cartilage from was diminished because of a defect in the core protein of the proteoglycans resulting in an impaired ability of these molecules to interact with hyaluronic acid.other sources, most of the proteoglycans in these tissues did not exist in large aggregates. Treatment with hyaluronic acid pl 4 3 hydrolase failed to diminish the size of proteoglycans prepared under conditions favoring aggregation, a finding suggesting that they were not complexed with hyaluronic acid. Polyacrylamide gel electrophoresis failed to demonstrate the presence of link glycoproteins associated with the proteoglycans. After incubation in vitro witb hyaluronic acid, minimal augmentation of hydrodynamic size of the preparation occurred, an indication that hyaluronate-proteoglycan interaction had not taken place. These results suggest that proteoglycan aggregation

Development and Reversal of a Proteoglycan Aggregation Defect In Normal Canine Knee Cartilage After Immobilization

“…T h e aggregation defect in the present study is similar to that described in morphologically normal hip cartilage from some aged individuals with recent femoral neck fractures (6). It is different, however, from the aggregation defect n o t e d i n articular cartilage of younger individuals whose joints had not been used normally for some time (7).…”

“…Aggregation defects similar to those of OA in morphologically and histochemically normal hip cartilage from aged humans have been recently demonstrated by the authors (6). In other samples from aged individuals (4), however, and in cartilage from younger persons (less than 50 years old), PG aggregation has been normal.…”

Glycosaminoglycans in horses with osteoarthritis

“…Because degeneration of articular cartilage with loss and fragmentation of the proteo lycans is an important feature of OA (Perricone, Palmoski and Brandt 1977), and because OA is so common in horses, a study was performed to determine the concentration of GAGs in synovial fluid (SF), serum and urine of arthritic horses. …”

New knowledge of connective tissue ageing

“…Thus, while increasing age is associated with an increased interaction between proteoglycans and collagen it is also associated with a diminished capacity to form aggregates among proteoglycans that do not interact with the collagen. Perricone et al (1977) examined the aggregation behaviour of proteoglycans extracted from cartilages from aged persons. The cartilage appeared morphologically and histochemically normal.…”

“…When isolated proteoglycan subunits from hip cartilage were incubated with hyaluronic acid little change in the elution patterns from the agarose columns was effected, in contrast to the pronounced aggregation seen when hyaluronic acid was mixed with proteoglycan subunits from normal bovine knee joint cartilage. Thus, the proteoglycans from aged human hip joint and older lumbar discs appear unable to aggregate with hyaluronic acid, probably because of a defect in the hyaluronic acid binding region of the protein core of the proteoglycans (Adams and Muir, 1976;Perricone et al, 1977).…”