KERATAN SULFATE AS A POTENTIAL BIOMARKER OF LOADING OF THE INTERVERTEBRAL DISC

Study Design. A review of the literature. Objective. To investigate th e potential of serum levels of keratan sulfate as a biomarker of the e ffects of loading of the spine. Summary of Background Data. Exposure t o mechanical loading of the spine causes changes in metabolism of inte rvertebral discs, eventually leading to accelerated disc degeneration. This process is characterized by the degradation of proteoglycans, wh ich is reflected by an increase in the blood level of proteoglycan com ponents. The serum level of keratan sulfate, an epitope present on the se proteoglycan components, has been suggested as a marker of changes in metabolism of cartilaginous tissues. Methods. A review of the liter ature on serum keratan sulfate levels in relation to degenerative chan ges in cartilaginous tissue. Results. In a number of studies keratan s ulfate in serum was reported to be related to degeneration of articula r cartilage in patients with osteoarthritis. In addition, massive and rapid degradation of intervertebral discs was determined to result in a large rise in serum keratan sulfate levels. Whether degenerative cha nges of intervertebral discs induced by mechanical stress also cause a detectable increase in serum keratan sulfate should be subjected to f urther investigation. Conclusion. Quantification of keratan sulfate in serum offers a promising measure for the early effects of mechanical loading of the spine, but research is needed for validation.