Early modifications of biochemical markers of bone metabolism in spinal cord injury patients. A preliminary study.

Spinal cord injury is associated with the development of a rapid and severe osteoporosis which might reflect uncoupling between bone formation and resorption. A prospective study was made in 6 spinal cord injury patients followed up to 2-3 months after onset with various markers of a) bone formation: osteocalcin and C-terminal peptide of type I procollagen, b) bone resorption: pyridinolines and C-terminal telopeptide of type I collagen, c) connective tissue metabolism: amino-terminal propeptide of type III collagen (PIIINP). Preliminary results show that early after onset, bone formation was depressed as compared to dramatically increased bone resorption. Low bone formation rate lasted two weeks before it began to raise, while bone resorption showed a continuous tendency to increase. The dramatic increase in PIIINP levels might represent some attempt of bone to repair. This paper describes the evolution of various biochemical markers of bone and connective tissue metabolism after onset of paralysis and critically reviews the use of those markers in patients with spinal cord injury.