Expression of LBX1 in muscle and bone of adolescent idiopathic scoliosis in Chinese
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摘要Abstract Introduction: Adolescent idiopathic scoliosis (AIS) is the most common pediatric spinal deformity, affecting
1% to 4% of adolescents worldwide. Our studies have shown that 27% to 38% of girls with AIShave systemic
osteopenia. However, the true etiology of idiopathic scoliosis remains unknown and is considered to be mult ifactorial.
In recent genome-wide associat ion studies by us and others, a st rong association between AIS and SNPs near the
ladybird homeobox 1 (LBX1) locus was found. Expression of LBX1 has been reported in skeletal muscles. However,
the expression in bone t issues and its associat ion with AIS remains unknown. In this study, we aim to investigate the expression of LBX1 mRNA in bilateral paravertebral muscles and bones harvested from iliac crest in AIS Vs control subjects.

Materials and Methods: Eighteen AIS pat ients (14.7 ± 1.9 years old) and 3 non-AIS controls (14.3 ± 0.6 years old)
were included. Muscle samples were harvested from bilateral paravertebral muscles at the apical vertebral level. LBX1 mRNA expression was evaluated by the conventional real-time PCR. LBX1 expressions in bilateral aravertebral
muscles were compared in each group. The expression ratio, the expression at the convex side relat ive to the concave side, was compared between groups. Also, the expression ratio of LBX1 and curve severity was correlated in the AIS. In a separate cohort, iliac crest biopsies were retrieved from 9 AIS patients (14.1 ± 2.2 years old) and 5 non-AIS control (13.2 ± 2.8 years old). LBX1 mRNA expression was evaluated by the conventional real-time PCR. LBX1 expressions in the iliac crest were compared in each group. The expression ratio was also compared between the osteopenic and non-osteopenic AIS subgroups.

Results: In paravertebral muscle, the LBX1 expression in AIS group was higher than the controls (Figure 1). There
were a significantly higher LBX1 mRNA expression at the convex side (p<0.05). However, the expression ratio of LBX1 was not significantly correlated with Cobb angle (r=-0.181, p=0.473). On evaluating the expression ratio of LBX1 in iliac crest , the AIS group have a lowered expression than controls (p<0.01) (Figure 2). The AIS patient with osteopenia (evaluated with DEXA), (n=3) was found to have significantly lower expression of LBX1 than the non-osteopenic subgroup (n=6) (p<0.01).

Discussion: Differences in the LBX1 mRNA expression was found between AIS group Vs cont rols. In the AIS group,
the expression was also asymmet rically observed in the apical paraspinal muscles. This is the first study to show the lower mRNA LBX1 expression in the iliac crest in the AIS particularly in the subgroup with osteopenia. Although we were unable to conclude whether these results were primary or secondary change, the difference in LBX1 expression in AIS could have contributed to curve progression. The limitations of this current study is 1) the small sample size and 2) the use of iliac crest rather than vertebral tissue. Further studies to evaluate the LBX1 mRNA expression in transverse process and its relation with the adjacent paravertebral muscle using protein expression would be essent ial.

Significance: These findings suggest the possible cross-talk between muscle and bone homeostasis and their possible cont ribut ion to development or progression of the spinal deformity in AIS.
著者Gene C.W. Man, Nelson L.S. Tang, Wayne Y.W. Lee, Jiajun Zhang, Bobby K.W. Ng, LeiLei Xu, Qiu Yong, Jack C.Y. Cheng
會議名稱Orthopaedic Research Society (ORS) 2017 Annual Meeting
會議地點San Diego, California, USA

上次更新時間 2018-18-01 於 08:21