Introduction. Forelimb and tail amputations of 3-week-old C57BL/6 mice are known to yield spinal curves similar to adolescent idiopathic scoliosis (AIS). Our previous work showed that tamoxifen produces a significant decrease in severity of these curves. Vertebral osteoporosis was thought to be related to AIS. Interestingly, a histological pilot study has shown that scoliotic mice given tamoxifen were less osteoporotic than were controls. Raloxifene is an
Introduction. From the many human studies that attempt to identify genes for adolescent idiopathic scoliosis (AIS), the view emerging is that AIS is a complex genetic disorder with many predisposing genes exhibiting complex phenotypes through environmental interactions. Although advancements in genomic technology are transforming how we undertake genetic and genomic studies, only some success has been reached in deciphering complex diseases such as AIS. Moreover, the present challenge in AIS research is to understand the causative and correlative effects of discovered genetic perturbations. An important limitation to such investigations has been the absence of a method that can easily stratify patients with AIS. To overcome these challenges, we have developed a functional test that allows us to stratify patients with AIS into three functional subgroups, representing specific endophenotypes. Interestingly, in families with multiple cases of AIS, a specific endophenotype is shared among the affected family members, indicating that such a transmission is inherited. Moreover, increased vulnerability to AIS could be attributable to sustained exposure to osteopontin (OPN), a multifunctional cytokine that appears to be at the origin of the Gi-coupled receptor signalling dysfunction discovered in AIS. We examined the molecular expression profiles of patients with AIS and their response to OPN. Methods. Osteoblasts isolated from patients with AIS were selected for each functional subgroup and compared with osteoblasts obtained from healthy matched controls. We used the latest gene chip human genome array Affymetrix (HuU133 Plus 2.0 array) that allows for the analysis of the expression level of 38 000 well characterised human genes. Raw data were normalised with robust multiarray analysis method. Statistical analysis was done by the EB method with FlexArray software. Selection criteria for in-depth analysis include the magnitude of change in expression (at least □} 3-fold) and 5% false discovery rate as stringency selection. Validation of selected candidate genes was done by qPCR and at the protein level by Western blot and ELISA methods. Plasma OPN concentrations were measured by ELISA on a group of 683 consecutive patients with AIS and were compared with 262 healthy controls and 178 asymptomatic offspring, born from at least one scoliotic parent, and thus considered at risk of developing the disorder. The regulation of OPN signalling pathway in normal and AIS cells were validated in vitro by cellular dielectric spectroscopy (CDS). Results. Of 38 000 human genes tested, we have found eight genes specifically associated with the functional subgroup 1, 16 genes with the functional subgroup 2, and 11 genes with the functional subgroup 3. Interestingly, only 19 genes were shared and affected to the same extent in all AIS functional subgroups exhibiting a similar curve pattern (double major), suggesting their role in the formation of this curve pattern. Indeed, most of these genes encode for regulatory proteins such as transcription factors regulating axial skeleton, somite development, and extracellular matrix proteins. Mean plasma OPN concentrations were significantly increased in patients with AIS and correlated with disease severity. Increased plasma OPN concentrations were also detected in the asymptomatic at-risk group, suggesting that these changes precede scoliosis onset. CDS experiments clearly showed that OPN exposure triggers a Gi-coupled receptor signalling dysfunction, which is exacerbated by
Adolescent idiopathic scoliosis affects about
3% of children. Non-operative measures are aimed at altering the natural
history to maintain the size of the curve below 40° at skeletal
maturity. The application of braces to treat spinal deformity pre-dates
the era of evidence-based medicine, and there is a paucity of irrefutable
prospective evidence in the literature to support their use and
their effectiveness has been questioned. This review considers this evidence. The weight of the evidence
is in favour of bracing over observation. The most recent literature
has moved away from addressing this question, and instead focuses
on developments in the design of braces and ways to improve compliance. Cite this article:
Low bone mass and osteopenia have been described in the axial and peripheral skeleton of patients with adolescent idiopathic scoliosis (AIS). Recently, many studies have shown that gene polymorphism is related to osteoporosis. However, no studies have linked the association between IL6 gene polymorphism and bone mass in AIS. This study examined the association between bone mass and IL6 gene polymorphism in 198 girls with AIS. The polymorphisms of IL6-597 G→A, IL6-572 G→C and IL6-174 G→A and the bone mineral density in the lumbar spine and femoral neck were analysed and compared with their levels in healthy controls. The mean bone mineral density at both sites in patients with AIS was decreased compared with controls (p = 0.0022 and p = 0.0013, respectively). Comparison of genotype frequencies between AIS and healthy controls revealed a statistically significant difference in IL6-572 G→C polymorphism (p = 0.0305). There was a significant association between the IL6-572 G→C polymorphism and bone mineral density in the lumbar spine, with the CC genotype significantly higher with the GC (p = 0.0124) or GG (p = 0.0066) genotypes. These results suggest that the IL6-572 G→C polymorphism is associated with bone mineral density in the lumbar spine in Korean girls with AIS.
