Abnormal leptin bioavailability in adolescent idiopathic scoliosis: an important new finding

Gut microbiota alterations in adolescent idiopathic scoliosis: a comparison study with healthy control and congenital scoliosis

PURPOSE

This study aims to compare the composition of GM isolated from individuals with AIS or congenital scoliosis (CS) and age-matched control (Ctr).

METHODS

A total of 48 patients with AIS, 24 patients with CS, and 31 healthy individuals were recruited as the discovery cohort, and 9 pairs of siblings where one was affected by AIS were recruited as the validation cohort. The GM profile was determined with 16S rRNA sequencing, and the alpha-diversity and beta-diversity metrics were performed with Mothur. Linear discriminant analysis (LDA) analysis was performed to identify the enriched species.

RESULTS

The α diversity (Chao1 index) was significantly lower in AIS patients with low BMI (< 18.5) than those with normal BMI. The PcoA analysis showed a trend of clustering of GM in AIS compared to that in Ctr and CS groups (r2 = 0.0553, p = 0.001). METASTAT analysis showed Cellulomonadaceae was significantly enriched in AIS groups compared to CS and Ctr. LDA analysis showed 9 enriched species in AIS patients. Compared to Ctr, two species including Hungatella genus and Bacteroides fragilis were significantly enriched, while the Firmicutes versus Bacteroidetes (F/B) ratio and the Ruminococcus genus were significantly decreased in AIS but not CS groups. The significantly reduced F/B ratio and Ruminococcus genus in AIS were replicated in the validation cohort.

CONCLUSIONS

Our study elucidated an association between low BMI and GM diversity in AIS patients. The reduced F/B ratio and Ruminococcus genus in AIS patients were identified and validated in 9 pairs of AIS patients and their unaffected siblings. Our pilot results may help understand the anthropometric discrepancy in these patients and support a possible role of GM in the pathogenesis of AIS.

Is refractive error a factor affecting scoliosis?

BACKGROUND

Scoliosis is one of the most common surgical disorders of the pediatric spine. Refractive errors are commonly associated with vision impairment worldwide. However, it is currently unclear whether refractive error correlates directly with the development of scoliosis.

METHODS

A cross-sectional study was performed in 2023, and a stratified cluster sampling technique was employed among school-aged students in Nantong City, China. Univariate and multivariate logistic regression analyses were used to investigate specific correlations between scoliosis and related parameters; various types of refractive errors were also included in the study.

RESULTS

The prevalence of scoliosis among school-aged students was 2.2% in Nantong city. Multiple logistic regression analyses showed that myopia, hyperopia, astigmatism, and anisometropia were not correlated with the development of scoliosis (all, p≥0.05). Lower body mass index (BMI) [adjusted odds ratio (aOR) = 0.92; 95% confidence interval (CI): 0.88-0.95; p<0.001], living in rural areas (aOR = 1.40; 95% CI: 1.05-1.86; p = 0.020), and older age (aOR = 1.32; 95% CI: 1.25-1.38; p<0.001) had significantly higher risks of scoliosis.

CONCLUSIONS

Refractive errors did not correlate with the development of scoliosis. However, BMI, living in rural areas and older age did correlate with the development of scoliosis.

Association between the GLP1R A316T Mutation and Adolescent Idiopathic Scoliosis in French Canadian and Italian Cohorts

Studies have revealed anthropometric discrepancies in girls with adolescent idiopathic scoliosis (AIS) compared to non-scoliotic subjects, such as a higher stature, lower weight, and lower body mass index. While the causes are still unknown, it was proposed that metabolic hormones could play a role in AIS pathophysiology. Our objectives were to evaluate the association of GLP1R A316T polymorphism in AIS susceptibility and to study its relationship with disease severity and progression. We performed a retrospective case-control association study with controls and AIS patients from an Italian and French Canadian cohort. The GLP1R rs10305492 polymorphism was genotyped in 1025 subjects (313 non-scoliotic controls and 712 AIS patients) using a validated TaqMan allelic discrimination assay. Associations were evaluated by odds ratio and 95% confidence intervals. In the AIS group, there was a higher frequency of the variant genotype A/G (4.2% vs. 1.3%, OR = 3.40, p = 0.016) and allele A (2.1% vs. 0.6%, OR = 3.35, p = 0.017) than controls. When the AIS group was stratified for severity (≤40° vs. >40°), progression of the disease (progressor vs. non-progressor), curve type, or body mass index, there was no statistically significant difference in the distribution of the polymorphism. Our results support that the GLP1R A316T polymorphism is associated with a higher risk of developing AIS, but without being associated with disease severity and progression.

Gut Microbiota Alterations in Adolescent Idiopathic Scoliosis Are Associated with Aberrant Bone Homeostasis

OBJECTIVE

Low bone mineral density is the major prognostic factor for adolescent idiopathic scoliosis (AIS), but the underlying mechanisms remain unclear. Accumulating evidence suggests that gut microbiota (GM) have the potential to affect bone development, and the GM signatures are altered in AIS patients. However, the effect of GM alterations on aberrant bone homeostasis in AIS remains unclear. This study aims to investigate the GM profile in AIS patients with different bone mineral density (BMD) and explore the association between GM, osteopenia, and aberrant bone turnover.

METHODS

A total of 126 patients with AIS who received surgical treatment were retrospectively included in this study. We analyzed the composition of the GM by 16S rRNA sequencing and BMD by dual X-ray absorptiometry. Based on the BMD of the femur neck, the patients were divided into the osteopenia group (OPN) if the Z score < -1, and the normal (NOR) group if the Z score ≥ -1 SD compared to the healthy control. For the 16S rRNA sequencing, the raw reads were filtered to remove low-quality reads, and operational taxonomic units were identified with the Uparse program. Weighted UniFrac distance matrix for the beta-diversity metrics and principal coordinate analysis (PCoA) was performed, and the statistical comparisons were made with permutational multivariate analysis of variance (PERMANOVA) and analysis of similarity (ANONISM). Linear discriminant analysis effect size (LEfSe) was used to identify the enriched species in two groups. The "Random forest" was applied to determine the optimal biomarker for OPN according to the mean decrease in Gini value. The metabolic function was predicted by the Tax4Fun analysis. The Pearson correlation coefficient was used to evaluate the associations between GM species, bone turnover markers, and BMD.

RESULTS

The serum β-CTX was increased in the OPN group (n = 67) compared to the NOR group (n = 59). Patients in OPN groups showed significantly decreased α diversity indicated by the Shannon index. Principal coordinate analysis (PCoA) analysis showed significant clustering of GM between OPN and NOR groups. At genus level, the Escherichia-Shigella and Faecalibacterium were significantly enriched in the OPN group compared to that in the NOR group (p < 0.05), whereas the abundance of Prevotella was significantly decreased (p = 0.0012). The relative abundance of Megamonas and Prevotella was positively correlated with the femur BMD. The abundance of Escherichia-Shigella was negatively correlated with femur BMD and positively correlated with serum β-CTX levels. Functional analysis revealed significant differences in starch and sucrose metabolism, pyruvate and cysteine, and methionine metabolism between NOR and OPN groups.

CONCLUSION

The alterations of GM in AIS patients are correlated with osteopenia. The association between enriched species, BMD, and bone turnover markers provides novel diagnostic and therapeutic targets for the clinical management of AIS.

Association of polymorphism in leptin receptor gene with susceptibility of adolescent idiopathic scoliosis

PURPOSE

Abnormal leptin bioavailability has play key roles in the etiology of adolescent idiopathic scoliosis (AIS). Both leptin and its receptor levels may be modulated by the presence of genetic polymorphisms. This study aimed to evaluate the role of polymorphisms in the leptin (LEP) and its main receptor (LEPR) genes in the AIS susceptibility in girls.

METHODS

A retrospective case-control study was conducted with 189 AIS and 240 controls. LEP rs2167270 and LEPR rs2767485 polymorphisms were genotyped using a TaqMan validated assay. Associations were evaluated by odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

The AIS group showed a predominance of girls under 18 years old (n = 140, 74.1%), 148 (78.3%) had low or normal BMI, 111 (58.7%) had Cobb ≥ 45º and 130 (68.7%) were skeletally mature. Minor allele frequencies of rs2167270 and rs2767485 were 35.7% and 18.3%, for AIS and 35.6% and 25.4% for controls, respectively. LEPR rs2767485 T and TC + TT were associated with higher risk of AIS (OR = 1.53; 95% CI = 1.09-2.13 and OR = 1.84; 95% CI = 1.69-2.01, respectively), since CC genotype was only present in the control group. In addition, the LEP rs2167270 GA + AA was more frequent in low weight group (BMI ≤ 24.9) of girls with AIS. There was no significant association between LEP rs2167270 and AIS susceptibility, and LEPR rs2767485 and BMI.

CONCLUSION

The LEPR rs2767485 was associated with the genetic susceptibility of AIS and LEP rs2167270 with low BMI. These data can contribute to the identification of genetic biomarkers to improve the diagnosis and treatment.

Circulatory Adipokines and Incretins in Adolescent Idiopathic Scoliosis: A Pilot Study

Adolescent idiopathic scoliosis (AIS) is a three-dimensional malformation of the spine of unknown cause that develops between 10 and 18 years old and affects 2-3% of adolescents, mostly girls. It has been reported that girls with AIS have a taller stature, lower body mass index (BMI), and bone mineral density (BMD) than their peers, but the causes remain unexplained. Energy metabolism discrepancies, including alterations in adipokine and incretin circulatory levels, could influence these parameters and contribute to disease pathophysiology. This pilot study aims to compare the anthropometry, BMD, and metabolic profile of 19 AIS girls to 19 age-matched healthy controls. Collected data include participants' fasting metabolic profile, anthropometry (measurements and DXA scan), nutritional intake, and physical activity level. AIS girls (14.8 ± 1.7 years, Cobb angle 27 ± 10°), compared to controls (14.8 ± 2.1 years), were leaner (BMI-for-age z-score ± SD: -0.59 ± 0.81 vs. 0.09 ± 1.11, p = 0.016; fat percentage: 24.4 ± 5.9 vs. 29.2 ± 7.2%, p = 0.036), had lower BMD (total body without head z-score ± SD: -0.6 ± 0.83 vs. 0.23 ± 0.98, p = 0.038; femoral neck z-score: -0.54 ± 1.20 vs. 0.59 ± 1.59, p = 0.043), but their height was similar. AIS girls had higher adiponectin levels [56 (9-287) vs. 32 (7-74) μg/mL, p = 0.005] and lower leptin/adiponectin ratio [0.042 (0.005-0.320) vs. 0.258 (0.024-1.053), p = 0.005]. AIS participants with a Cobb angle superior to 25° had higher resistin levels compared to controls [98.2 (12.8-287.2) vs. 32.1 (6.6-73.8), p = 0.0013]. This pilot study suggests that adipokines are implicated in AIS development and/or progression, but more work is needed to confirm their role in the disease.

Biological effect of dysregulated LBX1 on adolescent idiopathic scoliosis through modulating muscle carbohydrate metabolism

BACKGROUND CONTEXT

Abnormal energy metabolism such as lower body weight and body mass index (BMI) and less fat mass is widely reported in patients with adolescent idiopathic scoliosis (AIS) and has been implicated in deformity development. However, the underlying mechanism is largely unclear. LBX1 is one of the promising AIS predisposing genes validated by multicenter studies.

PURPOSE

This study aimed to identify differentially expressed proteins (DEPs) relating to energy metabolism in AIS by using proteomic and metabolic analysis and to explore if the expression of these DEPs is associated with clinical parameters and modulated by LBX1.

STUDY DESIGN

This is a cross-sectional study using clinical data and biological samples followed by basic study using a cellular model.

PATIENT SAMPLE

Plasma samples were collected from Chinese girls with nonprogressive and progressive AIS (N=7 and 8, respectively) and age-matched healthy girls (N=50). Paraspinal muscle tissues were collected intraoperatively from concave and convex side of the apex of the major spinal curve in AIS (N=24) and either side from nonscoliosis patients (N=14).

OUTCOME MEASURES

Radiological Cobb angle and basic anthropometric data of recruited subjects were measured. The DEPs and metabolites were compared in plasma using proteomics and metabolomics technique. The relative expression of selected genes was measured in muscles.

METHODS

Plasma samples from AIS were collected at first clinical visit and were further divided into nonprogressive or progressive groups according to Cobb angle changes in 6-year follow-up. Age-matched healthy girls were recruited as control. High-performance liquid chromatography-mass spectrometry based proteomic analysis was carried out in three groups to identify DEPs and their annotated metabolic pathways. An independent cohort was used for validation by gas chromatography-mass spectrometry based metabolomic analysis. Paraspinal muscles were subjected to quantitative polymerase chain reaction (qPCR) followed by correlation analysis. Human skeletal muscle myoblast (HSMM) was used as the cellular model.

RESULTS

The likelihood of aberrant galactose metabolism and glycolysis was found to be associated with AIS curve progression as evidenced by the thirteen DEPs and seven related metabolites according to proteomic and metabolomic analysis. Some of the DEPs showed significantly altered expression in AIS concave and convex sides paraspinal muscles compared with those in nonscoliosis control. Four DEPs were found significantly and negatively correlated with LBX1 in AIS convex side paraspinal muscles. Overexpressing LBX1 in HSMM cells led to increased expression of three DEPs and decreased expression of three DEPs, respectively.

CONCLUSIONS

This is the first integrated proteomic and metabolomic analysis on AIS. Our findings show dysregulated galactose metabolism and glycolysis pathways in progressive group of AIS, suggesting the presence of abnormal energy metabolism at early stage of this disease, and their association with higher risk of progressing into more severe curvature. Evidence from ex vivo study with human muscle biopsies and in vitro study with human myoblast cells propose the possible effect of LBX1 on these two pathways in skeletal muscles. The present study provides new evidence of LBX1 function in AIS via modulating effect on the expression of energy metabolism related genes. This study might provide new insights into etiopathogenesis and development of novel treatment strategy targeting on abnormal body weight and BMI in patients with AIS. Additionally, the plasma proteomic and metabolomic studies suggested new candidates as biomarkers for establishing predictive model for AIS onset/progression.

Genetic animal modeling for idiopathic scoliosis research: history and considerations

PURPOSE

Idiopathic scoliosis (IS) is defined as a structural lateral spinal curvature ≥ 10° in otherwise healthy children and is the most common pediatric spinal deformity. IS is known to have a strong genetic component; however, the underlying etiology is still largely unknown. Animal models have been used historically to both understand and develop treatments for human disease, including within the context of IS. This intended audience for this review is clinicians in the fields of musculoskeletal surgery and research.

METHODS

In this review article, we synthesize current literature of genetic animal models of IS and introduce considerations for researchers.

RESULTS

Due to complex genetic and unique biomechanical factors (i.e., bipedalism) hypothesized to contribute to IS in humans, scoliosis is a difficult condition to replicate in model organisms.

CONCLUSION

We advocate careful selection of animal models based on the scientific question and introduce gaps and limitations in the current literature. We advocate future research efforts to include animal models with multiple characterized genetic or environmental perturbations to reflect current understanding of the human condition.

Predictive value of single-nucleotide polymorphisms in curve progression of adolescent idiopathic scoliosis

PURPOSE

Genetic diagnosis is a promising approach because several single-nucleotide polymorphisms (SNPs) associated with adolescent idiopathic scoliosis (AIS) progression have been reported. We review the predictive value of SNPs in curve progression of adolescent idiopathic scoliosis.

METHODS

We reviewed DNA-based prognostic testing to predict curve progression. Then, the multiple polymorphisms in loci related to AIS progression were also reviewed, and we elucidated the predictive value of SNPs from four functional perspectives, including endocrine metabolism, neuromuscular system, cartilage and extracellular matrix, enzymes, and cytokines.

RESULTS

The ScoliScores were less successful predictors than expected, and the weak power of predictive SNPs might account for its failure. Susceptibility loci in ESR1, ESR2, GPER, and IGF1, which related to endocrine metabolism, have been reported to predict AIS progression. Neuromuscular imbalance might be a potential mechanism of scoliosis, and SNPs in LBX1, NTF3, and SOCS3 have been reported to predict the curve progression of AIS. Susceptibility loci in SOX9, MATN1, AJAP1, MMP9, and TIMP2, which are related to cartilage and extracellular matrix, are also potentially related to AIS progression. Enzymes and cytokines play essential roles in regulating bone metabolism and embryonic development. SNPs in BNC2, SLC39A8, TGFB1, IL-6, IL-17RC, and CHD7 were suggested as predictive loci for AIS curve progression.

CONCLUSIONS

Many promising SNPs have been identified to predict the curve progression of AIS. However, conflicting results from replication studies and different ethnic groups hamper their reliability. Convincing SNPs from multiethnic populations and functional verification are needed.

Turning the Curve Into Straight: Phenogenetics of the Spine Morphology and Coordinate Maintenance in the Zebrafish

The vertebral column, or spine, provides mechanical support and determines body axis posture and motion. The most common malformation altering spine morphology and function is adolescent idiopathic scoliosis (AIS), a three-dimensional spinal deformity that affects approximately 4% of the population worldwide. Due to AIS genetic heterogenicity and the lack of suitable animal models for its study, the etiology of this condition remains unclear, thus limiting treatment options. We here review current advances in zebrafish phenogenetics concerning AIS-like models and highlight the recently discovered biological processes leading to spine malformations. First, we focus on gene functions and phenotypes controlling critical aspects of postembryonic aspects that prime in spine architecture development and straightening. Second, we summarize how primary cilia assembly and biomechanical stimulus transduction, cerebrospinal fluid components and flow driven by motile cilia have been implicated in the pathogenesis of AIS-like phenotypes. Third, we highlight the inflammatory responses associated with scoliosis. We finally discuss recent innovations and methodologies for morphometrically characterize and analyze the zebrafish spine. Ongoing phenotyping projects are expected to identify novel and unprecedented postembryonic gene functions controlling spine morphology and mutant models of AIS. Importantly, imaging and gene editing technologies are allowing deep phenotyping studies in the zebrafish, opening new experimental paradigms in the morphometric and three-dimensional assessment of spinal malformations. In the future, fully elucidating the phenogenetic underpinnings of AIS etiology in zebrafish and humans will undoubtedly lead to innovative pharmacological treatments against spinal deformities.

Female-Specific Susceptibility Locus in BOC and SEC16B are Associated with Adolescent Idiopathic Scoliosis

STUDY DESIGN

A genetic case-control study.

OBJECTIVES

To investigate whether the variants in BOC, SEC16B, and SH2D1B are sex-specifically and functionally associated with the susceptibility of adolescent idiopathic scoliosis (AIS) in Chinese Han population.

SUMMARY OF BACKGROUND DATA

A recent genome-wide association study identified three female-specific susceptibility loci of AIS in Japanese population. However, the association of these genes with AIS in other populations remains unclear. Further investigation of the functional role of the three genes was warranted.

METHODS

SNPs rs73235136, rs545608, and rs142502288 were genotyped in 1599 AIS patients and 2985 controls. Paraspinal muscle collected from 40 AIS and 30 lumber disc herniation patients during surgical interventions was used for gene expression analysis. The difference regarding genotype and allele frequency between patients and controls was analyzed by chi-square analysis. Expression of BOC and SEC16B was compared between AIS and lumber disc herniation patients by the Student t test. Pearson correlation analysis was performed to evaluate the relationship between gene expression level and clinical phenotypes.

RESULTS

SNPs rs73235136 of BOC and rs545608 of SEC16B were found to be remarkably associated with AIS only in females. Allele C of rs73235136 and allele G of rs545608 could significantly add to the risk of female AIS patients, with an odds ratio of 1.087 and 1.033, respectively. However, there was no significant difference between the male patients and controls regarding genotype or allele frequency of rs73235136 and rs545608. No polymorphism at rs142502288 was detected in either patients or controls, and all the subjects had genotype of AA. Moreover, tissue expression of BOC and SEC16B was significantly lower in AIS patients compared with controls. BOC expression was positively associated with bone mineral contents, and expression of SEC16B was negatively correlated with curve severity in AIS patients.

CONCLUSION

Female-specific variants in BOC and SEC16B were associated with AIS. Expression of BOC and SEC16B was significantly lower in AIS patients. The role of BOC and SEC16B in the development of AIS is worthy of further investigation.Level of Evidence: 3.

Idiopathic scoliosis: general characteristics and analysis of etiological theories (literature review)

Idiopathic scoliosis is a severe pathology of the musculoskeletal system that affects children and adolescents all over the world. The disease occurs in approximately 0.2-0.6% of the general population, and is the largest subgroup of spinal curvature in humans (70-90% of all known scoliosis cases). In idiopathic scoliosis, a threedimensional deformation of the vertebral column is formed, leading to the formation of a rib hump, curvature of the ribs and chest, asymmetry of the pelvis and impaired development of internal organs. The main feature of the disease is the spontaneous development of deformity during the growth of the child and the tendency to progress. Scoliosis is not only an orthopedic disease, but also a ignificant cosmetic, and, consequently, a psychological and social problem. The standard of treatment for scoliotic disease remains unchanged for a long time: observation, corset treatment and surgical correction. The prognosis for the development of pathology varies depending on the degree of deformation. The corset-therapy, hospitalization, surgery and treatment of chronic back pain have a negative impact on the psychoemotional state of children and adolescents. Despite significant advances in the methods of diagnosis of deformity, improvement of surgical treatment methods and in the study of pathogenesis, the etiological factor of pathology is still unknown. The search for the causes of idiopathic scoliosis covers almost all aspects of its possible origin: genetic, environmental, hormonal, metabolic, biochemical, neurological, and others. In recent decades, relevant theories of the development of scoliosis have been formulated, but none of the theories reveals the essence of the pathological process and has no clear justification. The greatest number of supporters is the genetic theory: genetic factors play a key role in the occurrence and development of idiopathic scoliosis. Understanding the underlying factors of the disease will enable prevention, early diagnosis, and identification of the risk groups of the patients in question.

A reduced-order model of the spine to study pediatric scoliosis

The S-shaped curvature of the spine has been hypothesized as the underlying mechanical cause of adolescent idiopathic scoliosis. In earlier work, we proposed a reduced-order model in which the spine was viewed as an S-shaped elastic rod under torsion and bending. Here, we simulate the deformation of S-shaped rods of a wide range of curvatures and inflection points under a fixed mechanical loading. Our analysis determines three distinct axial projection patterns of these S-shaped rods: two loop (in opposite directions) patterns and one Lemniscate pattern. We further identify the curve characteristics associated with each deformation pattern, showing that for rods deforming in a Loop1 shape the position of the inflection point is the highest and the curvature of the rod is smaller compared to the other two types. For rods deforming in the Loop2 shape, the position of the inflection point is the lowest (closer to the fixed base) and the curvatures are higher than the other two types. These patterns matched the common clinically observed scoliotic curves-Lenke 1 and Lenke 5. Our S-shaped elastic rod model generates deformations that are similar to those of a pediatric spine with the same sagittal curvature characteristics and it can differentiate between the clinically observed deformation patterns.

A Semi-Analytic Elastic Rod Model of Pediatric Spinal Deformity

The mechanism of the scoliotic curve development in healthy adolescents remains unknown in the field of orthopedic surgery. Variations in the sagittal curvature of the spine are believed to be a leading cause of scoliosis in this patient population. Here, we formulate the mechanics of S-shaped slender elastic rods as a model for pediatric spine under physiological loading. Second, applying inverse mechanics to clinical data of the subtypes of scoliotic spines, with characteristic 3D deformity, we determine the undeformed geometry of the spine before the induction of scoliosis. Our result successfully reproduces the clinical data of the deformed spine under varying loads, confirming that the prescoliotic sagittal curvature of the spine impacts the 3D loading that leads to scoliosis.

Disordered leptin and ghrelin bioactivity in adolescent idiopathic scoliosis (AIS): a systematic review and meta-analysis

Background

Adolescents with scoliosis consistently demonstrate lower body weight, lean muscle mass, and bone mineral density than healthy adolescent counterparts. Recent studies have focused on understanding how leptin and ghrelin signaling may play a role in adolescent idiopathic scoliosis (AIS). In our current study, we aim to evaluate the serum levels of leptin, soluble leptin receptor (sOB-R), and ghrelin in AIS patients through systematic review and meta-analysis.

Methods

We conducted our systematic review by searching the keywords in online databases including PubMed, Embase, Cochrane, Elsevier, Springer, and Web of Science from the time of database inception to January 2020. Inclusion criteria were studies that measure leptin, soluble leptin receptor (sOB-R), and ghrelin levels in AIS patients. Selection of studies, assessment of study quality, and data extraction were performed by two reviewers independently. Then, data was analyzed to calculate the mean difference and 95% confidence interval (CI).

Results

Seven studies concerning leptin/sOB-R and three studies concerning ghrelin were qualified for meta-analysis (one study concerning both leptin and ghrelin). Serum leptin of patients with AIS were significantly lower when compared with healthy controls, with the weighted mean difference (WMD) of − 0.95 (95% CI − 1.43 to − 0.48, p < 0.0001) after reducing the heterogeneity using six studies for meta-analysis, while sOB-R and ghrelin level was significantly higher in AIS group when compared with control group, with the WMD of 2.64 (95% CI 1.60 to 3.67, p < 0.001) and 1.42 (95% CI 0.48 to 2.35, p = 0.003), respectively.

Conclusion

Our current meta-analysis showed that serum level of leptin in AIS patients was significantly lower when compared with control subjects, while serum sOB-R and ghrelin levels were significantly higher in AIS patients. More clinical studies are still required to further validate the predictive value of leptin or ghrelin for the curve progression for AIS patients.

Association between Bone Turnover Markers, Leptin, and Nutritional Status in Girls with Adolescent Idiopathic Scoliosis (AIS)

The link between scoliotic deformity and bone metabolism in adolescent idiopathic scoliosis (AIS) has not been well researched. Moreover, the data concerning the cross-talk between fat tissue content/hormonal activity and bone markers in this group of patients are lacking. The aim of the study was to assess whether there exists a significant relationship between the severity of AIS and bone turnover markers and leptin levels. The study group was consisted of 77 AIS girls, aged 14.7 ± 2.17 years. Scoliotic curve severity assessed by Cobb's angle was categorized as mild (10-19°), moderate (20-39°), or severe (≥40°). Corrected height, weight, and waist and hip circumferences were measured and body mass index (BMI), corrected height Z-score, BMI Z-score, and waist/height ratio (WHtR) were calculated for the entire group. Body composition parameters: fat mass (FAT), fat-free mass (FFM), and predicted muscle mass (PMM) were determined using a bioelectrical impedance analyzer. Bone turnover markers (osteocalcin (OC) and amino terminal of collagen cross-links (NTx) and leptin levels were assessed in serum. Multiple regression analysis showed that, OC, NTx (negatively with p < 0.05), and leptin (positively with p < 0.01) were significantly associated with curve severity in AIS girls. Moreover, Cobb's angle was positively correlated with W/HtR (p < 0.01) and FAT (p < 0.05). One-way analysis of variance (ANOVA) revealed significant differences in leptin (p < 0.05 vs. mild only), OC (p < 0.05 vs. mild and moderate), and W/HtR (p < 0.01 and p < 0.05 vs. mild and moderate, respectively) between the three AIS severity subgroups. OC was significantly lower in the severe AIS subgroup, while leptin and W/HtR were significantly higher. Significant correlations between leptin and anthropometrical parameters as BMI z-score and W/HtR were shown. Leptin level correlated also significantly with BMI z score (p < 0.001), W/HtR (p < 0.0001), and body composition parameters (p < 0.000001). Moreover, there was a significant negative correlation between NTx and leptin level (p < 0.05). Bone metabolism in AIS girls seems to be altered and significantly related to the scoliotic curve severity. Leptin may be a crucial link in the cross-talk between bone turnover and body composition in this group of patients. Further studies concerning interrelationship between nutritional status and bone metabolism in patients with AIS are warranted.

Incidence of scoliosis among junior high school students in Zhongshan city, Guangdong and the possible importance of decreased miR-30e expression

OBJECTIVE

We investigated scoliosis incidence among junior high school students in Zhongshan city, Guangdong, China and the expression of miR-30e among those with scoliosis.

METHODS

A total 41,258 students were included. From July 2015 to December 2017, all students underwent screening including routine observation of the standing and sitting posture, Adam's forward bend test, dorsal tilt angle measurement, and X-ray examination. Age, sex, height, weight, and body mass index (BMI) were recorded. Reverse transcription-quantitative polymerase chain reaction was used to assess miR-30e expression among students with scoliosis and 200 healthy students.

RESULTS

Overall, 743 students were diagnosed with scoliosis, with an incidence rate of 1.80%. A total 646 (86.9%) students were diagnosed with idiopathic scoliosis, 38 (5.1%) with congenital scoliosis, and 59 (7.9%) with other scoliosis types. Compared with healthy students, height was significantly greater whereas weight and BMI were significantly lower among students with scoliosis, and expression of miR-30e was significantly lower. However, no significant difference was found in height, weight, BMI, and mean Cobb angle between high/low miR-30e groups.

CONCLUSION

The incidence rate for scoliosis was 1.80%, Compared with healthy students, those with scoliosis were taller, had lower weight and BMI, and miR-30e expression was significantly downregulated.

Abnormal Osteoblastic Response to Leptin in Patients with Adolescent Idiopathic Scoliosis

Adolescent idiopathic scoliosis (AIS) is a complex three-dimensional structural deformity of the spine with unknown etiology. Although leptin has been postulated as one of the etiologic factors in AIS, its effects on osteoblastic activity remain unknown. Herein, we conducted this study to investigate whether there are abnormal functional responses to leptin and abnormal expression of leptin receptor in AIS osteoblasts. In vitro assays were performed with osteoblasts isolated from 12 severe AIS girls and 6 non-AIS controls. The osteoblasts were exposed to different concentrations of leptin (0, 10, 100, 1000 ng/mL). The effects of leptin on cell proliferation, differentiation and mineralization were determined. Protein expressions of leptin receptor (LEP-R) under basal and osteogenic conditions were also evaluated by Western blot. Our results showed that leptin significantly stimulated osteoblasts from non-AIS subjects to proliferate, differentiate and mineralized. However, in the AIS group, the stimulatory effects of leptin on cell proliferation, differentiation, and mineralization were not observed. In addition, no statistically significant difference in the expression of leptin receptor under both basal and osteogenic conditions was found between AIS and control group. In conclusion, these findings might help to explain the low bone mass and deranged bone quality that is clinically associated with AIS girls.

High Ghrelin Level Predicts the Curve Progression of Adolescent Idiopathic Scoliosis Girls

Background

Adolescent idiopathic scoliosis (AIS) is common deformity with unknown cause. Previous studies have suggested the abnormal serum leptin and ghrelin level in AIS girls. The aim of present study was to evaluate whether the serum leptin and ghrelin level could serve as risk factor in predicting the curve progression in AIS girls. The associations between them and the physical characteristics were also investigated.

Materials and Methods

Circulating leptin and ghrelin levels from 105 AIS girls and 40 age-matched non-AIS girls were examined by enzyme-linked immunosorbent assay. The correlations between ghrelin and leptin levels and growth-related parameters (age, weight, corrected height, corrected BMI, main Cobb angle, and Risser sign) were analyzed in AIS group. Multivariate logistic regression was used to investigate factors predicting curve progression in AIS girls.

Results

A significantly lower leptin level (6.55 ± 2.88 vs. 8.01 ± 3.12 ng/ml, p < 0.05) and a higher ghrelin level (6.33 ± 2.46 vs. 4.46 ± 2.02 ng/ml, p < 0.05) were found in all AIS patients, as compared with normal controls. Curve progression patients had a higher ghrelin level than stable curve patients (7.61 ± 2.48 vs. 5.54 ± 2.11 ng/ml, p < 0.01); for leptin level, there was no significant difference between progression and stable group. The results of multivariate logistic stepwise regression showed that premenarche status, initial main Cobb magnitude that was more than or equal to 23°, high ghrelin level (≥7.30 ng/ml), and lower Risser grade (grades 0 to 2) were identified as risk factors in predicting curve progression. Ghrelin levels of >6.48 ng/ml were predictive for curve progression with 70.00 % sensitivity and 72.31 % specificity, and the area under the curve (AUC) was 0.741 (95 % confidence interval 0.646-0.821).

Conclusions

High ghrelin level may serve as a new quantitative indicator for predicting curve progression in AIS girls.

Etiological Theories of Adolescent Idiopathic Scoliosis: Past and Present

Adolescent idiopathic scoliosis is one of the most common spinal deformities, yet its cause is unknown. Various theories look to biomechanical, neuromuscular, genetic, and environmental origins, yet our understanding of scoliosis etiology is still limited. Determining the cause of a disease is crucial to developing the most effective treatment. Associations made with scoliosis do not necessarily point to causality, and it is difficult to determine whether said associations are primary (playing a role in development) or secondary (develop as a result of scoliosis). Scoliosis is a complex condition with highly variable expression, even among family members, and likely has many causes. These causes could be similar among homogenous groups of AIS patients, or they could be individual. Here, we review the most prevalent theories of scoliosis etiology and recent trends in research.

A Case-Control Study of Body Composition, Prevalence, and Curve Severity of the Patients With Adolescent Idiopathic Scoliosis in the East Part of China

OBJECTIVE

The purpose of the study is to investigate the characteristics of prevalence and curve severity in patients with adolescent idiopathic scoliosis (AIS) and the body composition alterations between the patients with AIS and healthy controls.

METHODS

Information on the study sample was obtained from a screening database. The AIS cohort was paired with an age- and gender-matched healthy cohort. The stratification of BMI and curve severity was conducted according to the criteria developed by the US Centers for Disease Control and Prevention and the Scoliosis Research Society. The prevalence and curve severity of the patients with AIS were investigated. Multigroup comparison of body composition parameters was conducted according to BMI between the patients with AIS and healthy controls.

RESULTS

A total of 1,202 patients with AIS and an age- and gender-matched cohort were recruited from local schools. The underweight cases had the highest prevalence of AIS and significantly higher Cobb angle compared with the other three BMI subgroups. Although the patients with AIS had lower body weight, body fat mass, percentage of body fat, and fat-free mass compared with healthy controls, converse results were observed in the underweight cases after stratification according to BMI.

CONCLUSION

Based on the sporadic body composition of the patients with AIS observed in the current study, it is predictable that the pathophysiological alterations may be different before and after the onset of scoliosis. Well-designed human or animal studies for underweight patients would be helpful to reveal the mechanisms of pathophysiological alterations and better predict the development of AIS.

Dipeptidyl Peptidase-4 and Adolescent Idiopathic Scoliosis: Expression in Osteoblasts

It has been proposed that girls with adolescent idiopathic scoliosis (AIS) tend to have a taller stature and a lower body mass index. Energy homeostasis, that is known to affect bone growth, could contribute to these characteristics. In circulation, dipeptidyl peptidase-4 (DPP-4) inactivates glucagon-like peptide-1 (GLP-1), an incretin that promotes insulin secretion and sensitivity. Our objectives were to investigate DPP-4 status in plasma and in osteoblasts of AIS subjects and controls and to evaluate the regulatory role of metabolic effectors on DPP-4 expression. DPP-4 activity was assessed in plasma of 113 girls and 62 age-matched controls. Osteoblasts were isolated from bone specimens of AIS patients and controls. Human cells were incubated with glucose, insulin, GLP-1 and butyrate. Gene and protein expressions were evaluated by RT-qPCR and Western blot. Our results showed 14% inferior plasma DPP-4 activity in AIS patients when compared to healthy controls (P = 0.0357). Similarly, osteoblasts derived from AIS subjects had lower DPP-4 gene and protein expression than controls by 90.5% and 57.1% respectively (P < 0.009). DPP-4 expression was regulated in a different manner in osteoblasts isolated from AIS participants compared to controls. Our results suggest a role for incretins in AIS development and severity.

Brace technology thematic series: the 3D Rigo Chêneau-type brace

Background

Chêneau and Matthias introduced in 1979 a brace concept inspired in casting. The brace was initially named “CTM” from Chêneau-Toulouse-Münster. The name “CTM” is still popular in France but “Chêneau-type brace” is its common name in the rest of the world. Principles to construct this brace were originally based on anatomical descriptions rather than biomechanics, and its standard is poor.

Methods

This paper follows the format of the “Brace technology thematic series.” The Chêneau-type brace has been versioned by many authors. The contribution of the present authors is about to the description of the principles based on biomechanics and a specific classification created to help to standardize the brace design and construction. The classification also correlates with specific exercises (PSSE) according to the Barcelona School, using Schroth principles (BSPTS). This current authors’ version has been named “3D Rigo Chêneau-type brace.” The 3D principles are related to a detorsional mechanism created by forces and counterforces to bring the trunk into the best possible correction: (1) three-point system; (2) regional derotation; (3) sagittal alignment and balance. A custom-made TLS brace (thoracolumbosacral) is built in order to provide highly defined contact areas, which are located, shaped, and oriented in the space to generate the necessary vectors of force to correct in 3D. Expansion areas are also essential for tissue migration, growth, and breathing movements, although body reactions depend basically on how well designed are the contact areas. The brace is open in front and can be considered rigid and dynamic at the same time.

Results

Blueprints for construction of the brace according to the revisited Rigo classification are fully described in this paper.

Conclusions

Different independent teams have published comparable outcomes by using Chêneau-type braces and versions in combination with specific exercises and following a similar scoliosis comprehensive care model. This present version is also supported by scientific results from several independent teams.

Leptin Receptor Metabolism Disorder in Primary Chondrocytes from Adolescent Idiopathic Scoliosis Girls

To investigate the underlying mechanisms of low metabolic activity of primary chondrocytes obtained from girls with adolescent idiopathic scoliosis (AIS); AIS is a spine-deforming disease that often occurs in girls. AIS is associated with a lower bone mass than that of healthy individuals and osteopenia. Leptin was shown to play an important role in bone growth. It can also regulate the function of chondrocytes. Changes in leptin and Ob-R levels in AIS patients have been reported in several studies. The underlying mechanisms between the dysfunction of peripheral leptin signaling and abnormal chondrocytes remain unclear; The following parameters were evaluated in AIS patients and the control groups: total serum leptin levels; Ob-R expression in the plasma membrane of primary chondrocytes; JAK2 and STAT3 phosphorylation status. Then, we inhibited the lysosome and proteasome and knocked down clathrin heavy chain (CHC) expression in primary chondrocytes isolated from girls with AIS and evaluated Ob-R expression. We investigated the effects of leptin combined with a lysosome inhibitor or CHC knockdown in primary chondrocytes obtained from AIS patients; Compared with the controls, AIS patients showed similar total serum leptin levels, reduced JAK2 and STAT3 phosphorylation, and decreased cartilage matrix synthesis in the facet joint. Lower metabolic activity and lower membrane expression of Ob-R were observed in primary chondrocytes from the AIS group than in the controls. Lysosome inhibition increased the total Ob-R content but had no effect on the membrane expression of Ob-R or leptin’s effects on AIS primary chondrocytes. CHC knockdown upregulated the membrane Ob-R levels and enhanced leptin’s effects on AIS primary chondrocytes; The underlying mechanism of chondrocytes that are hyposensitive to leptin in some girls with AIS is low plasma membrane Ob-R expression that results from an imbalance between the rate of receptor endocytosis and the insertion of newly synthesized receptors into the membrane.

Understanding the role of the immune system in adolescent idiopathic scoliosis: Immunometabolic CONnections to Scoliosis (ICONS) study protocol

INTRODUCTION

Adolescent idiopathic scoliosis (AIS) affects up to 3% of children around the world. There is limited knowledge of AIS aetiopathogenesis, and this evidence is needed to develop new management strategies. Paraspinal muscle in AIS demonstrates evidence of differential fibrosis based on curve sidedness. Fibrosis is the hallmark of macrophage-driven inflammation and tissue remodelling, yet the mechanisms of fibrosis in paraspinal muscle in AIS are poorly understood.

OBJECTIVES

The primary objective of this study is to determine the influence of curve sidedness on paraspinal muscle inflammation. Secondary objectives include defining the mechanisms of macrophage homing to muscle, and determining muscle-macrophage crosstalk in muscle fibrosis in AIS.

METHODS AND ANALYSIS

This is a cross-sectional study conducted in a tertiary paediatric centre in Hamilton, Ontario, Canada. We will recruit boys and girls, 10-17 years of age, who are having surgery to correct AIS. We will exclude children who have an active infection or are on immunosuppressive therapies within 2 weeks of surgery, smokers and pregnant girls. Paraspinal muscle biopsies will be obtained at the start of surgery. Also, blood and urine samples will be collected from participants, who will fill questionnaires about their lifestyle. Anthropometric measures will also be collected including height, weight, waist and hip circumferences.

ETHICS AND DISSEMINATION

This study has received ethics authorisation by the institutional review board. This work will be published in peer-reviewed journals and will be presented in oral and poster formats at scientific meetings.

DISCUSSION

This study will explore the mechanisms of paraspinal muscle inflammation, remodelling and fibrosis in AIS. This will help identify pathways and molecules as potential therapeutic targets to treat and prevent AIS. It may also yield markers that predict scoliosis progression and response to treatment in these children.

Adolescent idiopathic scoliosis: current concepts on neurological and muscular etiologies

Adolescent idiopathic scoliosis (AIS) is a frequent disease but its etiology remains unknown. Gender prevalence in females is already known and there are many suggested hypotheses to explain its origin and manifestation, like associated neurologic, muscular and connective tissue disorders. Literature reports have tried to analyze disease prevalence in selected populations, possible ways of inheritance, related genes location and their polymorphisms, which may play a role in the development of the deformity. The purpose of this paper is to review and update concepts on the origin and genetic influence on AIS.

Lower Muscle Mass and Body Fat in Adolescent Idiopathic Scoliosis Are Associated With Abnormal Leptin Bioavailability

STUDY DESIGN

This was a case-control study.

OBJECTIVE

This study aimed to investigate the body composition and its correlation with leptin and soluble leptin receptor (sOB-R) levels in girls with adolescent idiopathic scoliosis (AIS) and compared with healthy controls.

SUMMARY OF BACKGROUND DATA

Patients with AIS are associated with lower body weight, taller stature, lower body mass index (BMI), and deranged bone quality. Despite the widely reported lower BMI and body weight in girls with AIS, the body composition of these patients was not thoroughly studied with sufficient sample size. Leptin is an important factor in regulating energy and bone metabolism, and has been postulated as one of the etiologic factors of AIS.

METHODS

One hundred forty-eight AIS and 116 control girls aged 12 to 14 were recruited. Body composition was measured with bioelectrical impedance analysis. Caloric intake and physical activity level were assessed by food frequency and Baecke questionnaires respectively. Serum total leptin and sOB-R levels were measured with enzyme-linked immunosorbent assay, and free leptin index was calculated.

RESULTS

AIS girls had lower body weight and BMI, other anthropometric and sexual maturity parameters were comparable with controls. There were no difference in caloric intake and physical activity levels. After adjustment for physical activity level, AIS girls had lower skeletal muscle mass, lower body fat, and %body fat. Higher sOB-R and lower free leptin index were found in AIS girls after adjusted for age and body weight. Weaker correlations between serum total leptin, FLI, and body composition parameters were observed in AIS girls.

CONCLUSION

Results suggested that the lower body weight in AIS girls was contributed by both lower skeletal muscle mass and lower body fat. Altered leptin bioavailability also exists in AIS girls and could lead to lower body weight, lower BMI, and abnormal body composition that were manifested in AIS simultaneously.

LEVEL OF EVIDENCE

4.

Spot14/Spot14R expression may be involved in MSC adipogenic differentiation in patients with adolescent idiopathic scoliosis

The aim of the present study was to evaluate the different expression levels of thyroid hormone responsive (THRSP; Spot14)/S14 related, Mig12 (S14R) during bone marrow mesenchymal stem cell (BM-MSC) adipogenesis in adolescent idiopathic scoliosis (AIS) patients. MSCs were retrospectively isolated from AIS patients and controls, and adipogenic differentiation was induced. Total RNA was extracted for Affymetrix 3′-IVT expression profiling microarrays and compared with the results from healthy controls. The results were confirmed by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) validation and the protein expression levels of Spot14 and its paralogous gene S14R by western blotting and immunohistochemistry. A total of 300 significantly altered mRNAs were detected (111 upregulated and 189 downregulated) and confirmed by RT-qPCR. The mRNA expression levels of seven genes, including Spot14, were altered by >2-fold in AIS patients. Spot14/S14R was selected for further investigation. The results of the western blotting demonstrated that mRNA and protein expression levels of Spot14/S14R were significantly higher in AIS patients than the controls (P<0.05). Immunohistochemistry demonstrated Spot14 was expressed in 85% (17/20 cases) in adipose tissue samples from AIS patients and 23.1% (3/13 cases) of adipose tissue samples from controls. The positive ratio of Spot14 in adipose tissue samples from AIS was significantly higher than the controls (P<0.001). The results of the present study indicated that Spot14/S14R were differently expressed in MSC adipogenesis in AIS patients, and they may be important in the abnormal adipogenic differentiation in AIS.

Identification of candidate diagnostic biomarkers for adolescent idiopathic scoliosis using UPLC/QTOF-MS analysis: a first report of lipid metabolism profiles

Adolescent idiopathic scoliosis (AIS) is a complex spine deformity, affecting approximately 1–3% adolescents. Earlier diagnosis could increase the likelihood of successful conservative treatment and hence reduce the need for surgical intervention. We conducted a serum metabonomic study to explore the potential biomarkers of AIS for early diagnosis. Serum metabolic profiles were firstly explored between 30 AIS patients and 31 healthy controls by ultra high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry. Then, the candidate metabolites were validated in an independent cohort including 31 AIS patients and 44 controls. The results showed that metabolic profiles of AIS patients generally deviated from healthy controls in both the discovery set and replication set. Seven differential metabolites were identified as candidate diagnostic biomarkers, including PC(20:4), 2-hexenoylcarnitine, beta-D-glucopyranuronicacid, DG(38:9), MG(20:3), LysoPC(18:2) and LysoPC(16:0). These candidate metabolites indicated disrupted lipid metabolism in AIS, including glycerophospholipid, glycerolipid and fatty acid metabolism. Elevated expressions of adipose triglyceride lipase and hormone sensitive lipase in adipose tissue further corroborated our findings of increased lipid metabolism in AIS. Our findings suggest that differential metabolites discovered in AIS could be used as potential diagnostic biomarkers and that lipid metabolism plays a role in the pathogenesis of AIS.

Association of Body Composition with Curve Severity in Children and Adolescents with Idiopathic Scoliosis (IS)

The link between scoliotic deformity and body composition assessed with bioimpedance (BIA) has not been well researched. The objective of this study was to correlate the extent of scoliotic-curve severity with the anthropometrical status of patients with idiopathic scoliosis (IS) based on standard anthropometric measurements and BIA. The study encompassed 279 IS patients (224 girls/55 boys), aged 14.21 ± 2.75 years. Scoliotic curve severity assessed by Cobb's angle was categorized as moderate (10°-39°) or severe (≥40°). Corrected height, weight, waist and hip circumferences were measured and body mass index (BMI), corrected height z-score, BMI Z-score, waist/height ratio (WHtR) and waist/hip ratio (WHR) were calculated for the entire group. Body composition parameters: fat mass (FAT), fat-free mass (FFM) and predicted muscle mass (PMM) were determined using a bioelectrical impedance analyzer. The mean Cobb angle was 19.96° ± 7.92° in the moderate group and 52.36° ± 12.54° in the severe group. The corrected body heights, body weights and BMIs were significantly higher in the severe IS group than in the moderate group (p < 0.05). Significantly higher FAT and lower FFM and PMM were observed in the severe IS group (p < 0.05). The corrected heights and weights were significantly higher in patients with severe IS and normal weight (p < 0.01). Normal and overweight patients with a severe IS had significantly higher adiposity levels assessed by FAT, FFM and PMM for normal and BMI, BMI z-score, WHtR, FAT and PMM for overweight, respectively. Overweight IS patients were significantly younger and taller than underweight and normal weight patients. The scoliotic curve severity is significantly related to the degree of adiposity in IS patients. BMI z-score, WHtR and BIA seem to be useful tools for determining baseline anthropometric characteristics of IS children.

Polymorphism of rs2767485 in Leptin Receptor Gene is Associated With the Occurrence of Adolescent Idiopathic Scoliosis

STUDY DESIGN

A genetic association study of leptin receptor (LEPR) gene with adolescent idiopathic scoliosis (AIS) in the Chinese Han population.

OBJECTIVE

To determine whether LEPR gene polymorphisms are associated with the predisposition and/or disease severity of AIS.

SUMMARY OF BACKGROUND DATA

Patients with AIS were reported to have lower body mass index (BMI), abnormal leptin bioavailability, and systemic lower bone mass, which implied that leptin/LEPR signaling pathway may be implicated in the etiology of AIS. Previous association study of the polymorphisms in leptin gene did not show significant differences between AIS cases and controls. However, no study has been done to investigate the relationship between genetic polymorphisms of the LEPR gene and susceptibility to AIS.

METHODS

570 patients with AIS aged 10 to 18 years were enrolled, and 570 age-matched healthy subjects were recruited as controls. 6 single nucleotide polymorphisms (SNPs) (rs1137101, rs1137100, rs4655555, rs2767485, rs1751492, and rs8179183) of LEPR gene were selected. The polymorphisms were genotyped using the polymerase chain reaction (PCR)-based Invader assay. Case-control study was performed to define the contribution of the 6 SNPs to predisposition of AIS. 1-way analysis of variance (ANOVA) test was used to compare the mean Cobb angles and BMI among patients with different genotypes in case-only analyses. Statistical significance was set at P < 0.05.

RESULTS

Both the genotype and allele frequencies of SNP rs2767485 were significantly different between the patient with AIS and the control groups. No significant difference of allele frequency was noted in other 5 SNPs between the patients with AIS and the normal controls. Both the mean maximum Cobb angles and BMI of different genotype AIS groups were similar to each other for all the 6 SNPs (P > 0.05).

CONCLUSION

Polymorphism of rs2767485 in LEPR gene is associated with the occurrence of AIS, suggesting LEPR is a predisposition gene.

Role of Enhanced Central Leptin Activity in a Scoliosis Model Created in Bipedal Amputated Mice

STUDY DESIGN

An experimental study to investigate the role of enhanced central leptin activity in a bipedal mouse scoliosis model.

OBJECTIVE

To investigate the influence of enhanced central leptin activity on the development of scoliosis in mice, and to support Burwell's hypothesis that central leptin dysfunction is involved in the etiopathogenesis of idiopathic scoliosis.

SUMMARY OF BACKGROUND DATA

Significantly lower level of circulating leptin and higher level of soluble leptin receptor have been reported in adolescent idiopathic scoliosis compared with healthy adolescents, suggesting possible association between abnormal central leptin level and dysfunction.

METHODS

Amputation of forelimbs and tail was performed on 50 male C3H/HeJ mice at the age of 3 weeks. Then, the mice were randomly divided into 2 groups: Group A consisted of 25 mice treated with injection into the hypothalamus with lentivirus vectors that overexpressed leptin; and Group B involved the remaining 25 mice receiving intracerebral injection with the control vectors. Radiographs were obtained at 20th week to determine the presence of spinal deformity. The incidence of scoliosis and curve magnitude were compared between groups.

RESULTS

The body weight was initially found to be slightly lower in mice of Group A when compared with Group B. Significantly higher peripheral serum leptin level was found in leptin-overexpressing mice than control mice. Scoliosis developed in 23 mice of Group A (92%), with an average Cobb angle of 30.2°, and in 13 of Group B (52%), with an average Cobb angle of 18.4°, respectively. A higher incidence (P = 0.002) and more severe curve (P <0.001) were observed in Group A.

CONCLUSION

In this bipedal mouse scoliosis model, enhanced central leptin activity might not only increase the risk of developing a scoliosis, but also contribute to the progression of scoliosis.

LEVEL OF EVIDENCE

N/A.

Adolescent idiopathic scoliosis

Adolescent idiopathic scoliosis (AIS) is the most common form of structural spinal deformities that have a radiological lateral Cobb angle - a measure of spinal curvature - of ≥10(°). AIS affects between 1% and 4% of adolescents in the early stages of puberty and is more common in young women than in young men. The condition occurs in otherwise healthy individuals and currently has no recognizable cause. In the past few decades, considerable progress has been made towards understanding the clinical patterns and the three-dimensional pathoanatomy of AIS. Advances in biomechanics and technology and their clinical application, supported by limited evidence-based research, have led to improvements in the safety and outcomes of surgical and non-surgical treatments. However, the definite aetiology and aetiopathogenetic mechanisms that underlie AIS are still unclear. Thus, at present, both the prevention of AIS and the treatment of its direct underlying cause are not possible.

In Search of Biomarkers for Idiopathic Scoliosis: Leptin and BMP4 Functional Polymorphisms

Idiopathic scoliosis (IS) is the most common spinal disorder in children and adolescents. The current consensus on IS maintains that it has a multifactorial etiology with genetic predisposition factors. In the present study the association of two functional polymorphisms of leptin (rs7799039) and BMP4 (rs4898820) with susceptibility to IS and curve severity was investigated in a Bulgarian population sample. The molecular detection of the genotypes was performed by amplification followed by restriction technology. The statistical analysis was performed by Pearson's chi-squared test. This case-control study revealed no statistically significant association between the functional polymorphisms of leptin and BMP4 and susceptibility to IS or curve progression (p > 0.05). On the basis of these results the examined polymorphic variants of leptin and BMP4 could not be considered as genetic variants with predisposition effect or as risk factors for the progression of the curve. In addition, these results do not exclude a synergistic effect of the promoter polymorphisms of leptin and BMP4 in the etiology and pathogenesis of IS. The identification of molecular markers for IS could be useful for early detection and prognosis of the risk for a rapid progression of the curve. That would permit early stage treatment of the patient with the least invasive procedures.

Roles of leptin in bone metabolism and bone diseases

Adipose tissue has been more accepted as an active contributor to whole body homeostasis, rather than just a fat depot, since leptin, a 16 kDa protein, was discovered as the product of the obese gene in 1994. With more and more studies conducted on this hormone, it has been shown that there is a close relationship between adipose tissue and bone, which have important effects on each other. Bone is the source of many hormones, such as osteocalcin, that can affect energy metabolism and then the anabolism or catabolism of fat tissue. In contrast, the adipose tissue synthesizes and releases a series of adipokines, which are involved in bone metabolism through direct or indirect effects on bone formation and resorption. Interestingly, leptin, one of the most important cytokines derived from fat tissue, seems to account for the largest part of effects on bone, through direct or indirect involvement in bone remodeling and by playing a significant role in many bone diseases, such as osteoporosis, osteoarthritis, rheumatic arthritis, bone tumors and even fractures. In this review, we will discuss the progress in leptin research, particularly focusing on the roles of leptin in bone diseases.

Lack of association between suppressor of cytokine signaling-3 gene polymorphism and susceptibility and curve severity of adolescent idiopathic scoliosis

PURPOSE

To explore whether the suppressor of cytokine signaling-3 (SOCS3) gene polymorphisms are associated with the susceptibility and abnormal growth pattern of adolescent idiopathic scoliosis (AIS).

METHODS

Three hundred and ninety eight AIS girls aged 10-18 years old were enrolled, and 367 age-matched healthy girls were recruited as controls. Only patients who had Cobb angles larger than 20º were included in this study. Anthropometric parameters including body weight, height, and body mass index (BMI) were measured for AIS girls. Rs4969198 was selected as tagSNP to cover all of the related polymorphisms on SOCS3. Genotyping was performed using PCR-based Invader assay with the probe sets designed and synthesized by third wave. The genotyping results were read with an ABI PRISM7900HT sequence detection system (Applied Biosystems, Foster City, CA). A subgroup of 322 skeletally mature AIS patients who did not received bracing or any other conservative treatment previously were analyzed to define the contribution of rs4969168 on curve severity, body height, body weight, and BMI.

RESULTS

Rs4969198 was successfully genotyped. No significant difference of genotype frequencies from the Hardy-Weinberg equilibrium (HWE) test was noted for the AIS patients or the normal controls. Neither the genotype nor the allele frequencies of rs49691968 were significantly different between the AIS patients and the normal controls. Rs4969168 was not found to be associated with age, curve severity of scoliosis, and body height. AIS patients with AA genotype had significantly higher body weight and BMI than the patients with AG and GG genotype (P = 0.014).

CONCLUSIONS

The SOCS3 gene polymorphisms are not associated with the occurrence of AIS, but the gene polymorphism (rs4969168) is associated with abnormal growth pattern of AIS, indicating that SOCS3 gene might be a disease-modifying gene of AIS.

Association between components of body composition and scoliosis: a prospective cohort study reporting differences identifiable before the onset of scoliosis

There is an increasing body of research suggesting that low body weight is associated with scoliosis, but this is based on case-control studies, which are prone to bias. No studies have investigated the components of body weight: fat and lean mass. We have therefore carried out the first population-based prospective study of the association between fat and lean mass at age 10 years assessed by dual-energy X-ray absorptiometry (DXA), with presence of scoliosis at age 15 years using the Avon Longitudinal Study of Parents and Children (ALSPAC). All children with scoliosis at age 10 years were excluded. Of 5299 children at age 15 years, 312 (5.9%) had scoliosis. Our results show a negative association between body mass index (BMI)/body weight at age 10 years and scoliosis at age 15 years, with a 20% reduced risk of scoliosis per SD increase in BMI (odds ratio [OR], 0.80; 95% confidence interval [CI], 0.70-0.92; p = 0.001). This association with BMI/body weight reflects associations with both fat mass and lean mass. After adjustment for age, gender, leg length, and fat mass per SD increase in lean mass, there was a 20% reduced risk of scoliosis (OR, 0.80; 95% CI, 0.65-0.97) and per SD increase in fat mass there was a 13% reduced risk of scoliosis (OR, 0.87; 95% CI, 0.74-1.03). In terms of adipocyte function, an inverse association was seen between leptin at age 10 years and scoliosis (OR for scoliosis per SD increase in leptin of 0.78; 95% CI, 0.63-0.99), and a positive association between adiponectin at age 10 years and scoliosis (OR for scoliosis per SD increase in adiponectin of 1.44; 95% CI, 0.99-2.10). This is the first study to address the association between the individual components of body weight and scoliosis in a prospective cohort study, and shows altered body composition that is present before the onset of clinically detected scoliosis.

How 'idiopathic' is adolescent idiopathic scoliosis? A systematic review on associated abnormalities

Background

Despite more than a century of dedicated research, the etiology and pathogenesis of adolescent idiopathic scoliosis (AIS) remain unclear. By definition, ‘idiopathic’ implies an unknown cause. Nevertheless, many abnormalities concomitant to AIS have been described, often with the suggestion that these abnormalities are related to etio-pathogenesis. Insight in the concomitant abnormalities may assist in improving the understanding of the etiological pathways of AIS. We aimed to systematically review and synthesize available studies on abnormalities concomitant to AIS.

Methods

Original studies comparing untreated AIS patients with healthy adolescents on abnormalities other than the deformity of the spine were retrieved from PubMed and Embase. We followed PRISMA guidelines and to quantify the relationship between each abnormality and AIS we used a best-evidence-syntheses for relating risk-of-bias to consistency of effect sizes.

Results

We identified 88 relevant citations, forty-seven carried high risk-of-bias and twenty studies did not report quantitative data in a sufficient manner. The remaining twenty-one publications failed to report data from before initiation of the deformity and blind assessments. These cross-sectional studies provided data on fourteen abnormalities concomitant to AIS. With our best-evidence-syntheses we were unable to find both strong evidence and a consistent pattern of occurrence for AIS and any of these abnormalities. From moderate risk-of-bias studies a relatively consistent pattern of occurrence for AIS and impaired gait control (4 studies; 155 subjects; Cohen’s d = 1.00) and decreased bone mineral density (2 studies; 954 subjects; Cohen’s d = −0.83) was found. For nine abnormalities a consistent pattern of occurrence with AIS was found, but the evidence for these was weak.

Conclusions

Based on the available literature, strong evidence is lacking for a consistent pattern of occurrence of AIS and any abnormality. The relevance for understanding the multifactorial etiology of AIS is very limited.

Increased Body Mass Index Negatively Affects Patient Satisfaction After a Posterior Fusion and Instrumentation for Adolescent Idiopathic Scoliosis

STUDY DESIGN

Retrospective.

SUMMARY OF BACKGROUND DATA

Previous studies have reported the correlation of body mass index (BMI) with non-spine surgical outcomes; however, only a few reviewed the correlation of BMI to outcomes after spine surgery.

OBJECTIVES

To review the influence of preoperative BMI on the follow-up clinical and functional outcomes after posterior-only fusion (PSF) and instrumentation for adolescent idiopathic scoliosis in a larger patient cohort.

METHODS

Retrospective review of a consecutive series of patients treated with PSF for adolescent idiopathic scoliosis from 2002 to 2009 at a single institution. There were 3 categories: underweight (UW), normal weight (NML), and overweight (OW). Percent correction of the major curve was collected at 2 years postoperatively and patient outcome scores were analyzed preoperatively and at 2 years postoperatively. Differences between groups were analyzed using analysis of variance, with p < .05.

RESULTS

A total of 459 patients at an average age of 15.0 years (range, 10.0-21.3 years) treated with PSF instrumentation were included. At 2 years, all groups achieved and maintained equal percent correction with no differences between groups. Regarding preoperative Scoliosis Research Society (SRS) outcome scores, OW patients reported more pain than NML (p = .002) and UW patients (p < .001) despite less reported activity than for the NML (p = .033) and UW groups (p = .005). The total SRS score was also lower in the OW patients compared with NML (p = .009) and UW patients (p = .002). At 2 years, the OW group reported more pain than the UW (p = .031) and NML groups (p = .018), lower mental scores (p = .011) and lower SRS total scores (p = .005) than the NML group.

CONCLUSIONS

At follow-up, preoperative overweight adolescents reported more pain and lower mental, activity, and appearance domain scores after surgery than UW and NML patients despite equal percent curve correction. This information may help the surgeon with preoperative counseling of OW patients by stressing that their own assessment of outcome is influenced by BMI, which may help promote a healthy weight management program in this patient group.

Are volumetric bone mineral density and bone micro-architecture associated with leptin and soluble leptin receptor levels in adolescent idiopathic scoliosis?--A case-control study

BACKGROUND

Adolescent idiopathic scoliosis (AIS) is associated with low bone mineral density (BMD). The underlying etiology and how it may relate to the development of osteopenia remains unknown. Leptin has been postulated as one of the etiologic factors of AIS because of its profound effects on bone metabolism and pubertal growth. Its modulator, soluble leptin receptor (sOB-R), may affect leptin bioavailability and signaling. This study aimed to investigate whether serum leptin and sOB-R levels may be associated with bone quality, and whether these relationships may differ between young adolescent girls with and without AIS.

METHODS

This was a case-control study involving 94 newly diagnosed AIS girls (Cobb angle 12-48°) aged 12 to 14 years old and 87 age and gender-matched normal controls. Subjects with BMI>23.0 Kg/m(2) were excluded. Anthropometric measurements including body weight, height, arm span and sitting height were taken. Serum total leptin and sOB-R were assayed with ELISA. Non-dominant distal radius was scanned with High Resolution pQCT for assessing bone quality in terms of bone morphometry, volumetric BMD (vBMD) and trabecular bone micro-architecture.

RESULTS

Compared with normal controls, AIS girls had numerically higher sOB-R (p = 0.006), lower average vBMD (p = 0.048), lower cortical vBMD (p = 0.029), higher cortical bone perimeter (p = 0.014) and higher trabecular area (p = 0.027), but none remained statistically significant after the Hochberg-Benjamini procedure. Correlation analysis on serum leptin level indicated that distinctive correlations with trabecular bone parameters occurred only in AIS.

CONCLUSION

This study showed that bone quality in AIS girls was deranged as compared with controls. In addition, the distinct differences in correlation pattern between leptin and trabecular bone parameters indicated possible abnormalities in bone metabolism and dysfunction of the leptin signaling pathway in AIS.

Body mass index in relation to truncal asymmetry of healthy adolescents, a physiopathogenetic concept in common with idiopathic scoliosis: summary of an electronic focus group debate of the IBSE

There is no generally accepted scientific theory for the cause of adolescent idiopathic scoliosis (AIS). As part of its mission to widen understanding of scoliosis etiology, the International Federated Body on Scoliosis Etiology (IBSE).introduced the electronic focus group (EFG) as a means of increasing debate on knowledge of important topics. This has been designated as an on-line Delphi discussion. The text for this debate was written by Dr TB Grivas. It is based on published research from Athens, Greece evaluating schoolchildren age 11-17 years for the relation of body mass index (BMI) to each of truncal asymmetry (TA) and menarcheal status. Girls with relatively lower BMI were found to have a significant excess of severe TAs and significantly later menarche confirming the well-known relation of BMI to menarche. Together with other evidence linking nutritional status to skeletal growth, the observations suggest energy balance via the hypothalamus is related to trunk asymmetry. As with a recent speculative hypothesis for the pathogenesis of AIS in girls, Grivas et al. suggest that the severe TAs involve a genetically-determined selectively increased sensitivity (up-regulation) of the hypothalamus to circulating leptin with asymmetry as an adverse response to stress (hormesis). The TA is expressed bilaterally via the sympathetic nervous system to produce left-right asymmetry in ribs and/or vertebrae leading to severe TAs when beyond the capacity of postural mechanisms of the somatic nervous system to control the shape distortion in the trunk. This EFG discusses the findings and interpretations of the paper by Grivas and colleagues as research at the borderland between the genesis of TA (physiogenesis) and AIS (pathogenesis). It is suggested that TAs, here regarded in common with AIS, result from the combination of secondary sexual development affecting body composition, adolescent skeletal growth velocity, and an asymmetry process. The possible involvement of epigenetic factors is not considered.

Analysis of single nucleotide polymorphism in adolescent idiopathic scoliosis in Korea: for personalized treatment

PURPOSE

The incidence of adolescent idiopathic scoliosis (AIS) has rapidly increased, and with it, physician consultations and expenditures (about one and a half times) in the last 5 years. Recent etiological studies reveal that AIS is a complex genetic disorder that results from the interaction of multiple gene loci and the environment. For personalized treatment of AIS, a tool that can accurately measure the progression of Cobb's angle would be of great use. Gene analysis utilizing single nucleotide polymorphism (SNP) has been developed as a diagnostic tool for use in Caucasians but not Koreans. Therefore, we attempted to reveal AIS-related genes and their relevance in Koreans, exploring the potential use of gene analysis as a diagnostic tool for personalized treatment of AIS therein.

MATERIALS AND METHODS

A total of 68 Korean AIS and 35 age- and sex-matched, healthy adolescents were enrolled in this study and were examined for 10 candidate scoliosis gene SNPs.

RESULTS

This study revealed that the SNPs of rs2449539 in lysosomal-associated transmembrane protein 4 beta (LAPTM4B) and rs5742612 in upstream and insulin-like growth factor 1 (IGF1) were associated with both susceptibility to and curve severity in AIS. The results suggested that both LAPTM4B and IGF1 genes were important in AIS predisposition and progression.

CONCLUSION

Thus, on the basis of this study, if more SNPs or candidate genes are studied in a larger population in Korea, personalized treatment of Korean AIS patients might become a possibility.

Whither the etiopathogenesis (and scoliogeny) of adolescent idiopathic scoliosis? Incorporating presentations on scoliogeny at the 2012 IRSSD and SRS meetings

This paper aims to integrate into current understanding of AIS causation, etiopathogenetic information presented at two Meetings during 2012 namely, the International Research Society of Spinal Deformities (IRSSD) and the Scoliosis Research Society (SRS). The ultimate hope is to prevent the occurrence or progression of the spinal deformity of AIS with non-invasive treatment, possibly medical. This might be attained by personalised polymechanistic preventive therapy targeting the appropriate etiology and/or etiopathogenetic pathways, to avoid fusion and maintain spinal mobility. Although considerable progress had been made in the past two decades in understanding the etiopathogenesis of adolescent idiopathic scoliosis (AIS), it still lacks an agreed theory of etiopathogenesis. One problem may be that AIS results not from one cause, but several that interact with various genetic predisposing factors. There is a view there are two other pathogenic processes for idiopathic scoliosis namely, initiating (or inducing), and those that cause curve progression. Twin studies and observations of family aggregation have revealed significant genetic contributions to idiopathic scoliosis, that place AIS among other common disease or complex traits with a high heritability interpreted by the genetic variant hypothesis of disease. We summarize etiopathogenetic knowledge of AIS as theories of pathogenesis including recent multiple concepts, and blood tests for AIS based on predictive biomarkers and genetic variants that signify disease risk. There is increasing evidence for the possibility of an underlying neurological disorder for AIS, research which holds promise. Like brain research, most AIS workers focus on their own corner and there is a need for greater integration of research effort. Epigenetics, a relatively recent field, evaluates factors concerned with gene expression in relation to environment, disease, normal development and aging, with a complex regulation across the genome during the first decade of life. Research on the role of environmental factors, epigenetics and chronic non-communicable diseases (NCDs) including adiposity, after a slow start, has exploded in the last decade. Not so for AIS research and the environment where, except for monozygotic twin studies, there are only sporadic reports to suggest that environmental factors are at work in etiology. Here, we examine epigenetic concepts as they may relate to human development, normal life history phases and AIS pathogenesis. Although AIS is not regarded as an NCD, like them, it is associated with whole organism metabolic phenomena, including lower body mass index, lower circulating leptin levels and other systemic disorders. Some epigenetic research applied to Silver-Russell syndrome and adiposity is examined, from which suggestions are made for consideration of AIS epigenetic research, cross-sectional and longitudinal. The word scoliogeny is suggested to include etiology, pathogenesis and pathomechanism.

Normal leptin expression, lower adipogenic ability, decreased leptin receptor and hyposensitivity to Leptin in Adolescent Idiopathic Scoliosis

Leptin has been suggested to play a role in the etiology of Adolescent Idiopathic Scoliosis (AIS), however, the leptin levels in AIS girls are still a discrepancy, and no in vitro study of leptin in AIS is reported. We took a series of case-control studies, trying to understand whether Leptin gene polymorphisms are involved in the etiology of the AIS or the change in leptin level is a secondary event, to assess the level of leptin receptor, and to evaluate the differences of response to leptin between AIS cases and controls. We screened all exons of Leptin gene in 45 cases and 45 controls and selected six tag SNPs to cover all the observed variations. Association analysis in 446 AIS patients and 550 healthy controls showed no association between the polymorphisms of Leptin gene and susceptibility/severity to AIS. Moreover, adipogenesis assay of bone mesenchymal stem cells (MSCs) suggested that the adipogenic ability of MSCs from AIS girls was lower than controls. After adjusting the differentiation rate, expressions of leptin and leptin receptor were similar between two groups. Meanwhile, osteogenesis assay of MSC showed the leptin level was similar after adjusting the differentiation rate, but the leptin receptor level was decreased in induced AIS osteoblasts. Immunocytochemistry and western blot analysis showed less leptin receptors expressed in AIS group. Furthermore, factorial designed studies with adipogenesis and osteogenesis revealed that the MSCs from patients have no response to leptin treatment. Our results suggested that Leptin gene variations are not associated with AIS and low serum leptin probably is a secondary outcome which may be related to the low capability of adipogenesis in AIS. The decreased leptin receptor levels may lead to the hyposensitivity to leptin. These findings implied that abnormal peripheral leptin signaling plays an important role in the pathological mechanism of AIS.

Adolescent idiopathic scoliosis (AIS), environment, exposome and epigenetics: a molecular perspective of postnatal normal spinal growth and the etiopathogenesis of AIS with consideration of a network approach and possible implications for medical therapy

Genetic factors are believed to play an important role in the etiology of adolescent idiopathic scoliosis (AIS). Discordant findings for monozygotic (MZ) twins with AIS show that environmental factors including different intrauterine environments are important in etiology, but what these environmental factors may be is unknown. Recent evidence for common chronic non-communicable diseases suggests epigenetic differences may underlie MZ twin discordance, and be the link between environmental factors and phenotypic differences. DNA methylation is one important epigenetic mechanism operating at the interface between genome and environment to regulate phenotypic plasticity with a complex regulation across the genome during the first decade of life. The word exposome refers to the totality of environmental exposures from conception onwards, comprising factors in external and internal environments. The word exposome is used here also in relation to physiologic and etiopathogenetic factors that affect normal spinal growth and may induce the deformity of AIS. In normal postnatal spinal growth we propose a new term and concept, physiologic growth-plate exposome for the normal processes particularly of the internal environments that may have epigenetic effects on growth plates of vertebrae. In AIS, we propose a new term and concept pathophysiologic scoliogenic exposome for the abnormal processes in molecular pathways particularly of the internal environment currently expressed as etiopathogenetic hypotheses; these are suggested to have deforming effects on the growth plates of vertebrae at cell, tissue, structure and/or organ levels that are considered to be epigenetic. New research is required for chromatin modifications including DNA methylation in AIS subjects and vertebral growth plates excised at surgery. In addition, consideration is needed for a possible network approach to etiopathogenesis by constructing AIS diseasomes. These approaches may lead through screening, genetic, epigenetic, biochemical, metabolic phenotypes and pharmacogenomic research to identify susceptible individuals at risk and modulate abnormal molecular pathways of AIS. The potential of epigenetic-based medical therapy for AIS cannot be assessed at present, and must await new research derived from the evaluation of epigenetic concepts of spinal growth in health and deformity. The tenets outlined here for AIS are applicable to other musculoskeletal growth disorders including infantile and juvenile idiopathic scoliosis.