Are Serum Bone Metabolic Markers Associated with Abnormal BMD and Bone Phenotypes in AIS?
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摘要Purpose: Low bone mineral density (BMD) and deranged peripheral cortical bone morphology
and trabecular bone micro-architecture was found in over 30% of Adolescent Idiopathic Scoliosis (AIS) patients and was recognized as a significant prognostic factor for curve progression. Our previous study also found impaired osteoblasts differentiation and structural and functional abnormal osteocytes lacuno-canalicular system in AIS. In this study we hypothesized that abnormal serum bone metabolic markers are associated with the abnormal bone phenotypes in AIS Vs normal controls.

Methods: This case-control recruited 47 AIS girls and 34 age-, gender- and ethnicity- matched healthy controls with recorded anthropometric data, pubertal maturity and curve severity. Left femoral neck areal BMD was measured with DXA, and volumetric BMD, cortical and trabecular bone phenotypes with HR-pQCT. Plate and rod trabecular configuration was further analyzed with individual trabecula segmentation (ITS) analysis (Figure 1). Serum bone metabolic markers, including osteocalcin, osteopontin, osteoprotegerin, parathyroid hormone (PTH), dickkopf-related protein 1 and sclerostin, were measured with Multiplex array. ANCOVA and partial correlation were performed with adjustment for age (SPSS, v19).

Results: The mean age of AIS and control subjects were 13.6 and 14.2, respectively. Cobb angle of the AIS subjects
is 32.8 ± 18.0 degrees. Comparing with controls, AIS had lower body weight and BMI. DXA and HR-pQCT revealed
significantly lower aBMD, cortical and trabecular vBMD associated with lower cortical area, cortical thickness
and trabecular area in AIS. Advanced ITS analysis showed significantly lower trabecular plate BV/TV and number, and connectivity density in AIS. AIS had significantly higher serum osteocalcin level (% difference = 32.9%) than controls. Despite small sample size, the discrepancies in bone phenotypes were consistent to our previous findings. In the control, serum osteocalcin level had significant negative correlation with cortical area and cortical thickness, and serum sclerostin were significantly correlated to rod and plate trabecular BV/TV. But, these distinctive correlation patterns were absent in AIS.

Conclusion: We report for the first time the abnormal relationship between bone phenotypes and serum osteocalcin and sclerostin, and provide additional evidence suggesting abnormal osteoblasts and osteocytes functional activities in AIS patients.

Significance: Considering osteocalcin is secreted by osteoblasts, and sclerostin by osteocytes. This study provides early evidence suggesting aberrant functional activities of these two cells in AIS. Further validation study with larger cohorts with different severities and in depth mechanistic study is warranted.
著者Bobby KW Ng, Huanxiong Chen, Wayne YW Lee, Ka-Yee Cheuk, Eric Yu, Fiona WP Yu; Elisa MS Tam, Tsz Ping Lam, Alec Lik Hang Hung, Feng Zhu, X. Edward Guo, Jack CY Cheng
會議名稱2017 Combined European Paediatric Orthopaedic Society (EPOS)/ Pediatric Orthopaedics Society of North America (POSNA) Annual Meeting (EPOSNA)
會議地點Barcelona, Spain

上次更新時間 2018-18-01 於 03:04