Figure 3. Treatment effects on serum bone marker turnover in placebo and MSDK groups. Bone formation markers (A) total procollagen type 1 amino-terminal propeptide (P1NP) and (B) osteocalcin (OC; both intact and N-terminal mid-fragments), serum bone resorption marker (C) Collagen Type I C-Telopeptide (CTx) were measured at months 0, 6 and 12. Serum samples were collected from participants (n=11 per group) and bone markers concentrations were measured by sandwich ELISA assay using commercially available specific bone marker kits at all three time points. Each point in the line graph represents the least square mean (± S.E.M.) in the bone markers concentration for placebo (open circle, red) and treatment (closed box, blue). Scatter plots represent the ratio of (D) CTx: P1NP and (E) CTx: OC for each study subject, respectively, where the solid lines indicate the mean (± S.E.M.) value for each group. *p ≤ 0.05 and **p ≤0.01 versus placebo at similar time points. Longitudinal analysis for repeated measures using a generalized linear mixed model (GLMM) approach, considering groups and times as fixed effects and subjects nested within the groups as random.