Urinary elimination of glycosaminoglycans during the immobilization osteoporosis of spinal cord injury patients.

Urinary glycosaminoglycans (GAGs) were measured in 47 paraplegics, six tetraplegics, and ten control subjects. In two paraplegics, the GAG rates were compared with those of hydroxyprolinuria and calciuria during one year. The GAG excretion rate found during the first five months after spinal cord injury increased significantly, up to three or four times the normal rate. No significant differences were found between paraplegics and tetraplegics. This increase in glycosaminoglycanuria parallels the previously reported increase in hydroxyprolinuria. The formation of a neurogenic paraosteoarthropathy showed the highest increase in hydroxyprolinuria. These biochemical assessments reflect the modifications in the bone matrix and cutaneous tissue associated with immobilization osteoporosis in spinal cord injury patients.