Collagen Crosslink Excretion in Monitoring of Mandibular Osteomyelitis

Objectives: Lysylpyridinoline (LP) and hydroxylysylpyridinoline (HP) are collagen crosslink residues of which the urinary concentrations reflect the level of connective-tissue turnover. HP is present in many tissues, whereas LP is specific for bone. The purpose of this investigation was to assess the possible value of urinary HP and LP concentrations in monitoring mandibular osteomyelitis. Methods: We investigated the following groups of patients. Group 1 consisted of patients with active mandibular osteomyelitis (n=10); group 2 consisted of group 1 patients six months after successful treatment (n=8). Group 3 was the control group (n=74, control group). The range and upper limit of normal values (HPmax and LPmax) were determined in group 3. Levels of LP and HP where measured by HPLC and fluorescence detection. Results: Urinary concentrations of HP and LP were within the normal range in four out of ten patients with confirmed mandibular osteomyelitis but there was a significant decrease (average 48.41% for HP and 50.36% for LP) in all samples of group 2 as compared to group 1 (p=0.012 for HP and LP). There was a significant difference of the average urinary levels of LP and HP between groups 1 and 3 (p=0.002 for HP and p<0.001 for LP) but none between groups 2 and 3. Conclusions: A decrease in the urinary concentration of HP and LP in patients with mandibular osteomyelitis may represent a measure of treatment success, and provide a tool for the monitoring of active disease.