Recent advances in the aetiology of adolescent idiopathic scoliosis

The Role of Muscle Biomarkers in Adolescent Idiopathic Scoliosis

Adolescent idiopathic scoliosis (AIS) is the predominant orthopedic disorder in children, affecting 1-3% of the global population. Research in this field has tried to delineate the genetic factors behind scoliosis and its association with heredity since AIS is considered a polygenic disease and has different genetic and epigenetic factors. The current study conducted a narrative review of the literature, focusing on biomarkers in the pathophysiology of muscle in AIS patients. Articles were collected from Scopus, Pubmed, and Web of Science. The key screening parameters were scoliosis classification, sampling, and the biomarkers evaluated. This review emphasizes potential key mechanisms and molecular regulators in muscle tissue. While there has been limited focus on the proteins contributing to muscle changes in AIS, significant attention has been given to genomic studies of single-nucleotide polymorphisms, particularly in LBX1. Despite these efforts, the exact causes of AIS remain elusive, with several theories suggesting genetic and hormonal factors. This review identified critical protein biomarkers such as Gi-protein alpha subunits, fibrillin-1 and -2, and various differentially expressed proteins, which may be linked to muscle alterations in AIS. This field of research is still limited due to a lack of homogeneity in the distinction of patients by groups and curve severity. Although the pathophysiology of AIS is still unclear, molecular research is important to guide the treatment of AIS before achieving skeletal maturity, thus avoiding serious problems associated with posture changes and low quality of life. In the future, a more comprehensive synergy between orthopedic and molecular research might ameliorate the diagnosis and treatment of AIS patients.

Schroth Physiotherapeutic Scoliosis-Specific Exercise (PSSE) Trials-Systematic Review of Methods and Recommendations for Future Research

The Schroth method is a non-operative treatment for scoliosis and kyphosis, used standalone or as an adjunct to bracing. While supporting evidence for its effectiveness is emerging, methodologic standardization and rigor are equivocal. Thus, we aimed to systematically review methods of published Schroth physiotherapeutic scoliosis-specific exercise (PSSE) trials and provide guidance for future research. We searched six databases for randomized controlled trials (RCT) and non-randomized studies of interventions (NRSIs) investigating the effect of Schroth in children and adults with scoliosis or kyphosis. General characteristics, methodological approaches, treatment protocols, and outcomes reporting were analyzed. Risk of bias (RoB) was assessed using an adapted Cochrane RoB2 tool for RCTs and ROBINS-I for NRSI. Eligible studies (n = 7) were conducted in six countries and included patients with Scheuermann's kyphosis (n = 1) and adolescent idiopathic scoliosis (n = 6). Though all seven studies used the term Schroth to describe their interventions, the Schroth method was used in four of seven studies, of which only one used Schroth classification, three used Schroth therapists, and none prospectively registered the study protocol. Overall, methodological rigor was suboptimal, potentially invalidating evidence synthesis. Authors should follow minimum standards for reporting, including prospectively registering detailed protocols; using appropriate exercise labeling, Schroth classification and certified therapists; naming and describing exercises per classification; and providing therapy dosages, prescription methods, and adherence.

The Impact of Training Time on Understanding the Treatment of Adolescent Idiopathic Scoliosis According to SOSORT International Guidelines: An Online Survey Study

The lack of knowledge by health professionals in the management of scoliosis can lead to an erroneous diagnosis. The aim of the current study was to understand the influence of length of professional experience on the knowledge of Brazilian physical therapists regarding international guidelines for the treatment of adolescent idiopathic scoliosis. The study was conducted using an online questionnaire consisting of 23 questions, divided into 8 questions on sociodemographic data and 15 questions based on information provided by the guidelines in the SOSORT 2016. In total, 506 physiotherapists were interviewed, and they comprised the study sample. The results showed that professionals who have been working for more than 6 years in the field have greater knowledge of AIS, seek to become more professional, and with that, have an understanding of AIS that is more aligned with the SOSORT. Length of experience made a difference when considering knowledge of the treatment of idiopathic scoliosis. The present study showed that a time since graduation of 6 years or more was satisfactory.

Analysis of the prevalence of asymmetry and muscle tone disorders in the first year of life among youth with idiopathic scoliosis: A retrospective case-control study

BACKGROUND

Not much is known about developmental motor disorders in the first year of life of children diagnosed with idiopathic scoliosis (IS).

OBJECTIVE

This study aimed to compare the occurrence of asymmetry or muscle tone disorders in the first year of life in adolescents with IS and their healthy counterparts.

METHODS

The parents of adolescents with IS and without scoliosis completed a survey on the occurrence of asymmetry, abnormal muscle tone, and physiotherapy in their children in the first year of life. Pearson's chi square test and Cramer's coefficient were used.

RESULTS

The final analysis included 527 surveys completed by parents of adolescents with idiopathic scoliosis (150) and without scoliosis (377). A significantly higher frequency of asymmetry (p= 0.001) and muscle tone disorders (p= 0.001) was noted in adolescents with idiopathic scoliosis. The results also revealed a significant association between scoliosis and asymmetry (p= 0.001), as well as muscle tone (p= 0.001).

CONCLUSIONS

Developmental asymmetry or improper muscle tone in the first year of life could be considered a potential factor in the development of scoliosis; however, this hypothesis should be confirmed in future studies. Infants diagnosed with developmental disorders require systematic observation.

Association of LBX1 Gene Methylation Level with Disease Severity in Patients with Idiopathic Scoliosis: Study on Deep Paravertebral Muscles

Idiopathic scoliosis (IS) is a multifactorial disease with a genetic background. The association of Ladybird Homeobox 1 (LBX1) polymorphisms with IS has been proven in multiple studies. However, the epigenetic mechanisms have not been evaluated. This study aimed to evaluate the LBX1 methylation level in deep paravertebral muscles in order to analyze its association with IS occurrence and/or IS severity. Fifty-seven IS patients and twenty non-IS patients were examined for the paravertebral muscles’ methylation level of the LBX1 promoter region. There was no significant difference in methylation level within paravertebral muscles between patients vs. controls, except for one CpG site. The comparison of the paravertebral muscles’ LBX1 promoter region methylation level between patients with a major curve angle of ≤70° vs. >70° revealed significantly higher methylation levels in 17 of 23 analyzed CpG sequences at the convex side of the curvature in patients with a major curve angle of >70° for the reverse strand promoter region. The association between LBX1 promoter methylation and IS severity was demonstrated. In patients with severe IS, the deep paravertebral muscles show an asymmetric LBX1 promoter region methylation level, higher at the convex scoliosis side, which reveals the role of locally acting factors in IS progression.

The Adolescent Spine

Adolescent idiopathic scoliosis (AIS) is the most characteristic disorder of the adolescent spine. It is a three-dimensional (3D) disorder that occurs from 10 years of age and comprises 90% of all idiopathic scolioses. Imaging plays a central role in the diagnosis and follow-up of patients with AIS. Modern imaging offers 3D assessment of scoliosis with less radiation exposure. Imaging helps rule out occult conditions that cause spinal deformity. Various imaging methods are also used to assess skeletal maturity in patients with AIS, thus determining the growth spurt and risk of progression of scoliosis. This article provides a brief overview of the pathophysiology, biomechanics, clinical features, and modern imaging of AIS relevant to radiologists in clinical settings.

[Etiology, epidemiology, prognosis and biomechanical principles of neuromuscular scoliosis]

Deformity due to neuromuscular disease is often progressive and associated with reduced vital capacity. In general, all treatment should be performed in specialized centers, since invasive measures are associated with an increased morbidity compared to adolescent scoliosis. Derived from the etiology and the resulting biomechanical basis (characteristics), important aspects and considerations arise for all healthcare institutions from the examination interval to the duration of conservative therapy and initiation of surgical therapy. Proper monitoring and assessment are key components to identify curve progression and to achieve preservation or improvement of basic functions.

Methylation of Estrogen Receptor 1 Gene in the Paraspinal Muscles of Girls with Idiopathic Scoliosis and Its Association with Disease Severity

Idiopathic scoliosis (IS) is a multifactorial disease with epigenetic modifications. Tissue dependent and differentially methylated regions (T-DMRs) may regulate tissue-specific expression of the estrogen receptor 1 gene (ESR1). This study aimed to analyze methylation levels within T-DMR1 and T-DMR2 and its concatenation with ESR1 expression of IS patients. The study involved 87 tissue samples (deep paravertebral muscles, both on the convex and the concave side of the curve, and from back superficial muscles) from 29 girls who underwent an operation due to IS. Patient subgroups were analyzed according to Cobb angle ≤70° vs. >70°. Methylation was significantly higher in the superficial muscles than in deep paravertebral muscles in half of the T-DMR1 CpGs and all T-DMR2 CpGs. The methylation level correlated with ESR1 expression level on the concave, but not convex, side of the curvature in a majority of the T-DMR2 CpGs. The T-DMR2 methylation level in the deep paravertebral muscles on the curvature's concave side was significantly lower in patients with a Cobb angle ≤70° in four CpGs. DNA methylation of the T-DMRs is specific to muscle tissue location and may be related to ESR1 expression regulation. Additionally, the difference in T-DMR2 methylation may be associated with IS severity.

Investigation of multidirectional hip range of motion and hip motion asymmetry in individuals with idiopathic scoliosis with different curve patterns

BACKGROUND

While some studies of the asymmetry of lower limbs in individuals with idiopathic scoliosis exist, there is a need for multidirectional studies conducted on hip joint range of motion and its relationship to curve patterns in idiopathic scoliosis.

OBJECTIVES

This study analyzes the hip joint range of multidirectional motions, hip motion asymmetry and investigates them according to curve patterns in individuals with idiopathic scoliosis.

METHODS

The sample included 108 females with idiopathic scoliosis. Participants were divided into three groups: double curves, single thoracic curve and single lumbar curve. The range of hip flexion and extension, abduction and adduction, and internal and external rotations were assessed actively and passively with a universal goniometer. The range of motion, left-right asymmetry and the mid-points of the ranges of motion were analyzed.

RESULTS

The passive range of the right hip abduction was higher in the thoracic curve group vs. the lumbar curve group. Active and passive ranges of hip extension were higher in the left hip vs. right hip. Active left-right asymmetry was higher than passive left-right asymmetry.

CONCLUSION

Individuals with idiopathic scoliosis had different hip abduction motions according to curve pattern that originated from single curves. Left-right hip asymmetry was seen for the hip extension motion. Higher left-right asymmetry for active motion than passive motion in hip abduction may indicate a problem in motion perception in individuals with idiopathic scoliosis.

Methylation of estrogen receptor 2 (ESR2) in deep paravertebral muscles and its association with idiopathic scoliosis

Idiopathic scoliosis (IS) is one of the most common spinal disorders in adolescents. Despite many studies, the etiopathogenesis of IS is still poorly understood. In recent years, the role of epigenetic factors in the etiopathogenesis of IS has been increasingly investigated. It has also been postulated that the development and progression of the disease is related to gender and puberty, and could be associated with estrogen action. Estrogen hormones act via estrogen receptor 1 (ESR1) and estrogen receptor 2 (ESR2). It has been suggested that ESR2 expression is dependent on methylation within its gene promoter. So far, no studies have evaluated local, tissue-specific DNA methylation in patients with IS. Thus, our study aimed to analyze the methylation and expression level of ESR2 in the paraspinal muscles of the convex and concave side of the IS curvature. The methylation level within ESR2 promoter 0N, but not exon 0N, was significantly higher on the concave side of the curvature compared to the convex side. There was no significant correlation between ESR2 expression and methylation level in the promoter 0N on the convexity of thoracic scoliosis, whereas, on the concave side of the curvature, we observed a moderate negative correlation. There was no difference in the methylation levels of the ESR2 promoter and exon 0N between groups of patients with Cobb angle ≤ 70° and > 70° on the concave and convex side of the curvature. We also found no statistically significant correlation between the Cobb angle value and the mean methylation level in either the ESR2 promoter or exon 0N on the convex or concave side of the curvature. Our findings demonstrate that DNA methylation at the ESR2 promoter in deep paravertebral muscle tissue is associated with the occurrence but not with the severity of idiopathic scoliosis.

Altered physiology of mesenchymal stem cells in the pathogenesis of adolescent idiopathic scoliosis

Adolescent idiopathic scoliosis is the most common spinal deformity during puberty, especially in females. It is characterized by aberrant skeletal growth and generalized reduced bone density, which is associated with impaired bone mineral metabolism. Despite recent progress in multidisciplinary research to support various hypotheses, the pathogenesis of Adolescent idiopathic scoliosis is still not clearly understood. One of the hypothesis is to study the role of mesenchymal stem cells due to its involvement in the above-mentioned bone metabolic abnormalities. In this review, we will summarize reported literatures on the role of mesenchymal stem cells, particularly in the pathogenesis of Adolescent idiopathic scoliosis. In addition, we will describe the research on mesenchymal stem cells of Adolescent idiopathic scoliosis performed using bioinformatics tools.

Current concepts in the diagnosis and management of adolescent idiopathic scoliosis

BACKGROUND

Adolescent Idiopathic Scoliosis (AIS) is a complex 3D structural disorder of the spine that has a significant impact on a person's physical and emotionalstatus. Thus, efforts have been made to identify the cause of the curvature and improve management outcomes.

AIM

This comprehensive review looks at the relevant literature surrounding the possible aetio-pathogenesis of AIS, its clinical features, investigations, surgicalmanagement options, and reported surgical outcomes in anterior spinal fusion, posterior spinal fusion or combined approach in the treatment of AIS.

Association of ESRα XbaI A > G, ESRα PvuII T > C and ESRβ AlwNI T > C Polymorphisms with the Risk of Developing Adolescent Idiopathic Scoliosis: A Systematic Review and Genetic Meta-analysis

Several association studies of genes polymorphisms on estrogen receptors-α and β with respect to adolescent idiopathic scoliosis (AIS) have been published in the past two decades. However, the association with AIS, especially among different ethnic subgroups, still remains controversial. Thus, we investigated these inconclusive data by performing a meta-analysis to systematically evaluate the association.

A literature search was conducted in the PubMed, ISI Web of Science, EMBASE, SCOPUS, EBSCO, Cochrane Library, China National Knowledge Infrastructure (CNKI) and Wanfang databases until January 20, 2018. The strength of relationship was assessed using odds ratios (ORs) and 95% confidence intervals (95%CIs).

A total of 12 case–control studies with 4,304 cases of AIS and 3,123 controls met our criteria. The pooled ORs indicated that the ESRα XbaI A > G, ESRα PvuII T > C and ESRβ AlwNI T > C polymorphisms were not significantly associated with the risk of developing AIS in the overall analysis. However, we found a significant association between the ESRα XbaI A > G polymorphism and AIS under the homozygote model (GG versus AA; OR = 1.448, 95%CI: 1.052–1.993; p  = 0.023).

The present meta-analysis suggests that the ESRα XbaI A > G, ESRα PvuII T > C and ESRβ AlwNI T > C polymorphisms may not be associated with the risk of developing AIS in the overall analysis. However, ESRα XbaI A > G might have an influence on the susceptibility to develop AIS among Asians. Considering the limited sample size and ethnicity, further larger studies are needed to provide a more precise estimation of the associations.

Evidence of Intrinsic Impairment of Osteoblast Phenotype at the Curve Apex in Girls With Adolescent Idiopathic Scoliosis

STUDY DESIGN

An observational descriptive study based on a single cohort of patients.

OBJECTIVE

To determine whether spinal facet osteoblasts at the curve apex display a different phenotype to osteoblasts from outside the curve in adolescent idiopathic scoliosis (AIS) patients.

SUMMARY OF BACKGROUND DATA

Intrinsic differences in the phenotype of spinal facet bone tissue and in spinal osteoblasts have been implicated in the pathology of AIS. However, no study has compared the phenotype of facet osteoblasts at the curve apex compared with outside the curve in AIS patients.

METHODS

Facet spinal tissue was collected perioperatively from three sites, the concave and convex side at the curve apex and from outside the curve (noncurve) from three AIS female patients aged 13-16 years. Spinal tissue was analyzed by micro-computed tomography to determine bone mineral density (BMD) and trabecular structure. Primary osteoblasts were cultured from concave, convex, and noncurve facet bone chips. The phenotype of osteoblasts was determined by assessment of cellular proliferation, cellular metabolism (alkaline phosphatase and Seahorse Analyzer), bone nodule mineralization (Alizarin red assay), and the mRNA expression of Wnt signaling genes (quantitative reverse transcriptase polymerase chain reaction).

RESULTS

Convex facet tissue exhibited greater BMD and trabecular thickness, compared with concave facet tissue. Osteoblasts at the convex side of the curve apex exhibited a significantly higher proliferative and metabolic phenotype and a greater capacity to form mineralized bone nodules, compared with concave osteoblasts. mRNA expression of SKP2 was significantly greater in both concave and convex osteoblasts, compared with noncurve osteoblasts. The expression of SFRP1 was significantly downregulated in convex osteoblasts, compared with either concave or noncurve.

CONCLUSIONS

Intrinsic differences that affect osteoblast function are exhibited by spinal facet osteoblasts at the curve apex in AIS patients.

LEVEL OF EVIDENCE

Level IV, Prognostic.

Prevalence of Adolescent Idiopathic Scoliosis in the State of São Paulo, Brazil

STUDY DESIGN

A cross-sectional study.

OBJECTIVE

To estimate the prevalence of adolescent idiopathic scoliosis (AIS) in cities in the state of São Paulo, Brazil, as well as to identify demographic, clinical, and lifestyle factors associated with AIS.

SUMMARY OF BACKGROUND DATA

AIS is a common three-dimensional spinal deformity. Epidemiological data about the condition in the southern hemisphere are scarce, and Brazil has no public health policies to implement school-based scoliosis screening programs.

METHODS

We assessed 2562 adolescents between 10 and 14 years of age. The screening procedure included measurement of the angle of trunk rotation using a scoliometer in the Adams forward bend test and the radiographic examination.

RESULTS

The overall prevalence of AIS was 1.5% (95% confidence interval [CI]: 1%-1.9%). The AIS prevalence was higher among the females than among the males-2.2% (95% CI: 1.4%-2.9%) and 0.5% (95% CI: 0.1%-0.9%), respectively. The following factors were associated with the development of AIS: being female (OR = 4.7, 95% CI: 1.8-12.2; P = 0.001) and being in the 13- to 14-year age group (OR = 2.2; 95% CI: 1.0-4.8; P = 0.035). Double curves and right laterality were more common (59.4% and 56.8%, respectively), although the curves were of low magnitude (75% of the curves having a Cobb angle ≤22°), as was the progression factor (≤1.2 in 75% of the cases).

CONCLUSION

The prevalence of AIS in cities within the state of São Paulo was similar to that reported in the literature, was higher among females, and was higher during puberty (13-14 years of age). Because puberty occurs later for males than for females, the recommendation to screen both sexes at 10 to 14 years of age should be reconsidered.

LEVEL OF EVIDENCE

3.

Value of DNA methylation in predicting curve progression in patients with adolescent idiopathic scoliosis

BACKGROUND

There is considerable discordance in the curve progression of adolescent idiopathic scoliosis (AIS) patients between monozygotic (MZ) twins, indicating that nongenetic factors must be involved in the curve progression of AIS patients. Epigenetic processes may constitute one of these factors and have not yet been investigated in relation to curve progression in AIS patients.

METHODS

The genome and methylome of peripheral monocytes were compared between MZ twins discordant for curve progression. Sets of differentially methylated sites were validated using the MassARRAY platform of Sequenome on additional samples.

RESULTS

In the discovery study, we found evidence suggesting a lack of differences at the genome sequence level and the presence of epigenetic differences related to the curve progression of AIS patients. The top 4 differentially methylated CpG sites associated with curve severity were tested, and only site cg01374129 (CpG site located at chr8:122583383, Hg19) was confirmed in two replication cohorts. The methylation levels of site cg01374129 were significantly lower in the progression group than in the nonprogression group. Cox regression analysis demonstrated that hypo-methylation of site cg01374129 was an independent prognostic factor for curve severity. Site cg01374129 methylation as a marker achieved a sensitivity of 76.4% and a specificity of 85.6% in differentiating between samples from patients with and without curve progression (AUC = 0.827; 95% CI: 0.780 to 0.876).

CONCLUSION

Increased curvature is associated with decreased methylation at site cg01374129. Our results indicate that methylation of site cg01374129 may therefore serve as a promising biomarker in differing between patients with and without curve progression.

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.

Abnormal osteogenic and chondrogenic differentiation of human mesenchymal stem cells from patients with adolescent idiopathic scoliosis in response to melatonin

Abnormalities of membranous and endochondral ossification in patients with adolescent idiopathic scoliosis (AIS) remain incompletely understood. To investigate abnormalities in the melatonin signaling pathway and cellular response to melatonin in AIS, a case-control study of osteogenic and chondrogenic differentiation was performed using human mesenchymal stem cells (hMSCs). AIS was diagnosed by physical and radiographic examination. hMSCs were isolated from the bone marrow of patients with AIS and control subjects (n=12 each), and purified by density gradient centrifugation. The expression levels of melatonin receptors (MTs) 1 and 2 were detected by western blotting. Osteogenic and chondrogenic differentiation was induced by culturing hMSCs in osteogenic and chondrogenic media containing vehicle or 50 nM melatonin. Alkaline phosphatase (ALP) activity assays, quantitative glycosaminoglycan (GAG) analysis, and reverse transcription-quantitative polymerase chain reaction analysis were performed. Compared with controls, MT2 demonstrated low expression in the AIS group. Melatonin increased ALP activity, GAG synthesis and upregulated the expression of genes involved in osteogenic and chondrogenic differentiation including, ALP, osteopontin, osteocalcin, runt-related transcription factor 2, collagen type II, collagen type X, aggrecan and sex-determining region Y-box 9 in the normal control hMSCs, but did not affect the AIS groups. Thus, AIS hMSCs exhibit abnormal cellular responses to melatonin during osteogenic and chondrogenic differentiation, which may be associated with abnormal membranous and endochondral ossification, and skeletal growth. These results indicate a potential modulating role of melatonin via the MT2 receptor on abnormal osteogenic and chondrogenic differentiaation in patients with AIS.

Identification of Differential Genes Expression Profiles and Pathways of Bone Marrow Mesenchymal Stem Cells of Adolescent Idiopathic Scoliosis Patients by Microarray and Integrated Gene Network Analysis

STUDY DESIGN

Microarray approach and integrated gene network analysis.

OBJECTIVE

To explore the differential genetic expression profile, gene ontology terms, and Kyoto Encyclopedia of Genes and Genomes pathways in bone marrow mesenchymal stem cells (BM-MSCs) of idiopathic scoliosis (AIS) and non-AIS controls.

SUMMARY OF BACKGROUND DATA

The pathogenesis of adolescent AIS and the accompanying generalized osteopenia remain unclear. Our previous study suggested increased proliferation ability and decreased osteogenic differentiation ability of BM-MSCs of AIS. Therefore, we hypothesized that MSCs may play a significant role in the etiology and pathogenesis of AIS.

METHODS

In this study, microarray analysis was used to identify differentially expressed genes (DEGs) of BM-MSCs from AIS patients compared with those from healthy individuals. Comprehensive bioinformatics analyses were then used to enrich datasets for gene ontology and pathway. Based on the gene signal transduction network analysis of DEGs contained in significant pathways, 24 potential crucial genes were selected for validation by reverse transcription polymerase chain reaction.

RESULTS

There are 1027 previously unrecognized DEGs in BM-MSCs from AIS patients. Pathway analysis revealed dysregulated mitogen-activated protein kinase (MAPK) signaling pathway, PI3K-Akt signaling pathway, calcium signaling pathway, peroxisome proliferator-activated receptor (PPAR) signaling pathway, ubiquitin-mediated proteolysis, and Notch signaling pathway, all of which have been reported to play an important role in regulating the osteogenic or adipogenic differentiation of MSCs. Furthermore, gene signal transduction networks analysis indicated that mitogen-activated protein kinase kinase 1 (MAP2K1), SMAD family member 3 (SMAD3), homeobox C6 (HOXC6), heat shock 70kDa protein 6 (HSPA6), general transcription factor IIi (GTF2I), CREB binding protein (CREBBP), phosphoinositide-3-kinase, regulatory subunit 2 (PIK3R2), and dual specificity phosphatase 2 (DUSP2) may play essential roles in AIS pathogenesis and accompanied osteopenia.

CONCLUSION

This study reports the differential genes expression profiles of BM-MSCs from AIS patients and related potential pathways for the first time. These previously unrecognized genes and molecular pathways might play a significant role in not only the causal mechanism of osteopenia in AIS, but also the AIS initiation and development. The identification of these candidate genes provides novel insight into the underlying etiological mechanisms of AIS.

LEVEL OF EVIDENCE

N/A.

Adolescent idiopathic scoliosis: evidence for intrinsic factors driving aetiology and progression

Adolescent idiopathic scoliosis (AIS) is now considered to be a multifactorial heterogeneous disease, with recent genomic studies supporting the role of intrinsic factors in contributing to the onset of disease pathology and curve progression. Understanding the key molecular signalling pathways by which these intrinsic factors mediate AIS pathology may facilitate the development of pharmacological therapeutics and the identification of predictive markers of progression. The heterogenic nature of AIS has implicated multiple tissue types in the disease pathophysiology, including spinal bone, intervertebral disc and paraspinal muscles. In this review, we highlight some of the mechanisms and intrinsic molecular regulators within these different tissue types and review the evidence for their involvement in AIS pathology.

MUSCLE DISORDERS IN ADOLESCENT IDIOPATHIC SCOLIOSIS: LITERATURE REVIEW

ABSTRACT Scoliosis is characterized by three-dimensional changes of the spine and is estimated to be present in 4% of the population worldwide. The most common form is the adolescent idiopathic. The purpose of this study is to identify the major muscle abnormalities found in patients with adolescent idiopathic scoliosis through a literature review. We conducted an electronic search of the national databases PubMed, Lilacs, PEDro, and EMBASE using the keywords "scoliosis", "biomechanics", "exercise", "physical therapy specialty", "idiopathic", and "muscles", from January 2003 to April 2015. The most relevant articles in English, Portuguese and Spanish were selected by title and abstract. It was also performed a manual search of the references of the selected articles. From a total of 4,319 articles, 11 were selected. We conclude that individuals with AIS have changes in the paraspinal muscles, with a difference in activation between the concave and convex sides, suggesting an increase in EMG activity on the convex side, although there is still no consensus among the authors.

Motor and somatosensory abnormalities are significant etiological factors for adolescent idiopathic scoliosis

OBJECTIVE

In adolescent idiopathic scoliosis (AIS), we explore the role of lateralized motor and somatosensory abnormalities as a possible etiological factor.

METHODS

Intraoperative transcranial electrical stimulation was performed in 15 AIS and 14 adult degenerative scoliosis (ADS) patients. Inter-side motor output balance (MOB) by comparing the ratios of right to left motor evoked potentials (MEP) amplitudes, and inter-side motor output excitability (MOE) computed with MEP amplitude, was determined separately for both patients groups. For somatosensory evoked potentials (SSEP), peak to peak P37 amplitudes from right and left lower limb SSEP and inter-side P37 amplitude ratios were obtained.

RESULTS

Inter-side MOB was significantly asymmetric in AIS patients, contributed mainly by inter-side MOB changes in the upper than the lower limbs. Inter-side MOE comparisons of ipsilateral and contralateral MEP amplitudes were significantly different between AIS and ADS patients. Mean upper limb MEP amplitudes were significantly reduced in AIS patients. Amplitude of the right upper limb MEPs were positively correlated with inter-side MEP ratio. AIS patients show larger mean MEP amplitudes on the same side as the scoliotic curve. Overall, no correlation of Cobb's angle or total levels of scoliosis involvement with inter-side MOB and MOE parameters was found. Inter-side SSEP ratios were significantly higher in AIS patients.

CONCLUSIONS

Primary dysfunctional and distributed motor output contributing to abnormalities of inter-side MOB and MOE changes involving the upper limbs is evident in AIS. Simultaneous but independent somatosensory and motor observations seen these patients suggest a central mechanism as an etiological factor.

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.

Surgical results with the use of Silicated Calcium Phosphate (SiCaP) as bone graft substitute in Posterior Spinal Fusion (PSF) for Adolescent Idiopathic Scoliosis (AIS)

BACKGROUND

The gold standard iliac crest bone graft (ICBG) used to achieve arthrodesis in spinal fusions is not without complications (donor-site morbidity, iliac wing fractures etc.…). Our objectives were to evaluate the role of silicated calcium phosphate (SiCaP), an osteoconductive synthetic bone graft substitute in conjunction with locally harvested autologous bone in achieving arthrodesis following posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS) and report clinic-radiological results / adverse events with its use in a prospective single surgeon case series (Level of evidence [LoE] IV) treated by low implant density index (IDI) constructs (i.e., IDI ≤1.5).

METHODS

Thirty-five patients (8♂ & 2727♀) who underwent PSF and followed-up for a minimum of 2 years formed the study cohort. The mean age at surgery was 15 years (range: 11-21y) and pre-op Cobb angle was 60° (range: 40°-90°). SiCaP mixed with locally harvested bone during exposure and instrumentation was laid over instrumented segments. The average SiCaP used per patient was 32mls (range: 10-60mls). Radiographs were assessed for fusion at serial six monthly follow-ups. All clinical adverse events and complications were recorded.

RESULTS

The mean follow-up was 2.94 years (range: 2-4y). The post-op Cobb angle improved to 23° (range: 2°- 55°) and the mean in-patient stay was 7.72 days (range: 5-13d). The mean number of instrumented segments was 9.4 (range: 4-13) and implant density index (IDI) averaged 1.23 (range: 1.15-1.5). Radiographic new bone formation was seen within 3 months in all cases. All patients (except two) were highly satisfied at minimum follow-up of 8 years. There were two complications warranting revision surgery (deep infection, and implant failure without any evidence of pseudarthrosis). There were no SiCaP specific adverse events in any of the 35 patients.

CONCLUSION

SiCaP facilitated early bony consolidation in operated cohort of AIS patients treated by PSF. There were no inflammatory reaction or other adverse effects associated with its use. SiCaP is a safe alternative to autologous iliac crest bone graft with reduced complications, morbidity, faster recovery and similar infection/fusion rates reported in the literature.

Animal models of scoliosis

Multiple techniques designed to induce scoliotic deformity have been applied across many animal species. We have undertaken a review of the literature regarding experimental models of scoliosis in animals to discuss their utility in comprehending disease aetiology and treatment. Models of scoliosis in animals can be broadly divided into quadrupedal and bipedal experiments. Quadrupedal models, in the absence of axial gravitation force, depend upon development of a mechanical asymmetry along the spine to initiate a scoliotic deformity. Bipedal models more accurately mimic human posture and consequently are subject to similar forces due to gravity, which have been long appreciated to be a contributing factor to the development of scoliosis. Many effective models of scoliosis in smaller animals have not been successfully translated to primates and humans. Though these models may not clarify the aetiology of human scoliosis, by providing a reliable and reproducible deformity in the spine they are a useful means with which to test interventions designed to correct and prevent deformity.

Participation of sex hormones in multifactorial pathogenesis of adolescent idiopathic scoliosis

PURPOSE

In order to verify the potential association between the aetiopathogenesis of adolescent idiopathic scoliosis (AIS) and the process of sexual maturation, we determined the concentrations of oestrogens in pre- and postmenarcheal girls affected by this condition. AIS, occurring mostly in pubescent girls, is one of the most frequent forms of faulty posture. Therefore, it was assumed that the multifactorial pathomechanism of AIS involves significant deficiency of oestrogens.

METHODS

The diagnosis of AIS was established on the basis of physical examination and analyses of radiograms. Concentrations of FSH, LH, oestrogens, progesterone, osteocalcin and RANKL were determined by ELISA. The activity of alkaline phosphatase (AP) was measured by kinetic method. The study included pre- and postmenarcheal girls with AIS and corresponding groups of scoliosis-free controls.

RESULTS

In premenarcheal scoliotic girls, the levels of FSH, LH and oestradiol were lower; the levels of progesterone, oestrone and oestriol were higher; and the concentrations of oestrone and oestriol were similar compared to premenarcheal controls. Higher levels of RANKL, osteocalcin and AP were observed in premenarcheal adolescents with AIS compared to controls. The concentrations of FSH, LH, oestradiol, and progesterone in postmenarcheal girls with scoliosis were lower, oestrone were slightly lower and oestriol did not differ compared with the control group. Significantly higher levels of RANKL, osteocalcin and AP were observed in postmenarcheal scoliotic adolescents compared with controls.

CONCLUSIONS

There is an interdependence between the concentration of oestradiol and development of scoliosis. Determination of estradiol may have diagnostic value in the screening of spinal pathologies associated with AIS.

Revisiting scoliosis in the KNM-WT 15000 Homo erectus skeleton

Owing to its completeness, the 1.5 million year old Nariokotome boy skeleton KNM-WT 15000 is central for understanding the skeletal biology of Homo erectus. Nevertheless, since the reported asymmetries and distortions of Nariokotome boy's axial skeleton suggest adolescent idiopathic scoliosis, possibly associated with congenital skeletal dysplasia, it is questionable whether it still can be used as a reference for H. erectus. Recently, however, the presence of skeletal dysplasia has been refuted. Here, we present a morphological and morphometric reanalysis of the assertion of idiopathic scoliosis. We demonstrate that unarticulated vertebral columns of non-scoliotic and scoliotic individuals can be distinguished based on the lateral deviation of the spinous process, lateral and sagittal wedging, vertebral body torsion, pedicle thickness asymmetry, and asymmetry of superior and inferior articular facet areas. A principal component analysis of the overall asymmetry of all seven vertebral shape variables groups KNM-WT 15000 within non-scoliotic modern humans. There is, however, an anomaly of vertebrae T1-T2 that is compatible with a short left convex curve at the uppermost thoracic region, possibly due to injury or local growth dysbalance. Asymmetries of the facet joints L3-L5 suggest a local right convex curve in the lower lumbar region that probably resulted from juvenile traumatic disc herniation. This pattern is incompatible with adolescent idiopathic scoliosis or other types of scoliosis, including congenital, neuromuscular or syndromic scoliosis. It is, however, consistent with a recent reanalysis of the rib cage that did not reveal any asymmetry. Except for these possibly trauma-related anomalies, the Nariokotome boy fossil therefore seems to belong to a normal H. erectus youth without evidence for adolescent idiopathic scoliosis or other severe pathologies of the axial skeleton.

Understanding the Basis of Genetic Studies: Adolescent Idiopathic Scoliosis as an Example

STUDY DESIGN

A review of the general concepts of genetics studies with specific reference to adolescent idiopathic scoliosis (AIS).

OBJECTIVES

To equip the average spine surgeon with the vocabulary and understanding needed to understand the genetics of scoliosis and the approaches used to identify risk genes.

SUMMARY OF BACKGROUND DATA

Adolescent idiopathic scoliosis is a multifactorial disease. Increasing evidence from families and monozygotic twins suggests the involvement of genetic factors. An estimation of heritability also indicates a strong influence of genetics on the disease. Increasing focus has been placed on identifying genes and genetic variants associated with AIS.

REVIEW

This is a review of genes and genetic variations, the phenotype definition of AIS in genetics studies, concepts and approaches to identifying associated genes, and the evaluation of results. Different types of genetic variations are present in the genome. These variations may modulate the expression or function of protein products, which in turn alter individuals' susceptibility to disease. Identifying the variants related to AIS requires an objective and clearly defined phenotype, among which the Cobb angle is commonly used. The phenotype helps classify subjects into cases and controls. By selecting candidate genes of growth factors and hormonal receptors, which are speculated to be involved in the mechanism of disease, the variants within these genes were compared between cases and controls to identify any differences. Another approach was to use large families and inspect the co-segregation of variants and phenotypes. Recently, arrays covering the variants of the whole genome were developed and assist in high-throughput screening for associated genes.

CONCLUSIONS

Genetic factors have an important role in AIS. Deciphering the genes and genetic variants associated with AIS can improve our understanding of the mechanisms of the disease, as well as assist in designing treatment methods and preventive measures.

Comparison of harrington rod and cotrel-dubousset devices in surgical correction of adolescent idiopathic scoliosis

Background

Since the time of Paul Harrington numerous implants have been introduced for correction of scoliosis, but none are ideal. Newer devices are very expensive, and in our country some patients cannot afford them.

Objectives

The aim of this study was to compare the results of the Harrington rod (HR) device and the newer Cotrel-Dubousset (CD) device in treatment of adolescent idiopathic scoliosis (AIS).

Materials and Methods

A retrospective review assessed patients with AIS admitted for spinal curve correction treated with HR (n = 120) and CD devices (n = 138) between October 1988 to April 2001 at the Shafa Yahyaeian Hospital, Tehran, Iran. We extracted information from the patient’s file and radiographs before, after and two years post-operation.

Results

The mean age of patients was 16.7 ± 2.5 years. There was no statistically significant difference between the two groups regarding gender, age, curve before surgery, and percentage of flexibility. The mean curvature was 70 ± 20.7 in the HR and 64.81 ± 19.4 in the CD group before surgery (P = 0.09); and the mean curvature was 40 ± 16.3 and 26.58 ± 15.37 in HR and CD groups respectively after surgery (P = 0.156). The mean curvature was 47.2 ± 15.9 in HR and 31.2 ± 15.4 in CD groups at two years follow-up (P = 0.156).

Conclusions

Results of many studies have shown no significant impairment in long-term quality of life and function in patients treated with Harrington rods. According to previously performed studies and the current study, surgical correction with Harrington rods seem to be comparable with the newer more expensive CD device. Although there is no doubt that the preference is to use newer devices in view of some disadvantages of HR, but this does not preclude using it for patients that cannot afford the newer devices.

Otolith dysfunction as a possible cause for the development of idiopathic scoliosis

BACKGROUND

To investigate whether otolith system, as a major contributor to muscles for postural control, might play a role in the pathogenesis of idiopathic scoliosis (IS).

METHODS

Cervical vestibular-evoked myogenic potentials (VEMP) testing was applied to investigate the otolith function in patients with IS. Twenty-nine healthy patients (mean age 13.5±2.5 y, 4 males) were included. In all but 2 patients, the major curve deviation was to the right and the mean angle deviation was 49.7±21.6 degrees. Nineteen age-matched individuals (10 males) served as controls.

RESULTS

The P13 (first positive wave) latencies were comparable in both groups. Patients with IS had significantly longer N23 (first negative wave) latencies than controls. A high correlation between the age and N23 latencies on the right was found in IS patients. A link between the scoliosis angle and VEMP latencies could not be demonstrated.The VEMP amplitudes were higher in patients than in controls, whereas the amplitude asymmetry ratio was similar in both groups.

CONCLUSIONS

This work brings further evidence for vestibular abnormalities in patients with IS. Prospective studies are needed to elucidate a possible causative relationship between otolith dysfunction and the development of scoliosis.

LEVEL OF EVIDENCE

III.

Restricted neural plasticity in vestibulospinal pathways after unilateral labyrinthectomy as the origin for scoliotic deformations

Adolescent idiopathic scoliosis in humans is often associated with vestibulomotor deficits. Compatible with a vestibular origin, scoliotic deformations were provoked in adult Xenopus frogs by unilateral labyrinthectomy (UL) at larval stages. The aquatic ecophysiology and absence of body-weight-supporting limb proprioceptive signals in amphibian tadpoles as a potential sensory substitute after UL might be the cause for a persistent asymmetric descending vestibulospinal activity. Therefore, peripheral vestibular lesions in larval Xenopus were used to reveal the morphophysiological alterations at the cellular and network levels. As a result, spinal motor nerves that were modulated by the previously intact side before UL remained permanently silent during natural vestibular stimulation after the lesion. In addition, retrograde tracing of descending pathways revealed a loss of vestibular neurons on the ipsilesional side with crossed vestibulospinal projections. This loss facilitated a general mass imbalance in descending premotor activity and a permanent asymmetric motor drive to the axial musculature. Therefore, we propose that the persistent asymmetric contraction of trunk muscles exerts a constant, uncompensated differential mechanical pull on bilateral skeletal elements that enforces a distortion of the soft cartilaginous skeletal elements and bone shapes. This ultimately provokes severe scoliotic deformations during ontogenetic development similar to the human syndrome.

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.

Pathogenesis and biomechanics of adolescent idiopathic scoliosis (AIS)

Adolescent idiopathic scoliosis is defined as a scoliosis that starts after the age of ten and has no clear underlying disease as a reason for its development. There is, however, a disparity between the growth of the vertebral bodies anteriorly and that of the posterior elements. The vertebral bodies grow faster than the posterior elements, resulting primarily in a lordosis. The diminished dorsal growth impedes the ventrally located vertebral bodies from increasing in height, forcing them to become distorted, i.e., rotate, in order to create space for themselves. This produces a rotational lordosis. The idea of looking at it in this way dates back to Somerville in 1952. Many recent studies have confirmed this idea and have shown that the spinal canal is shorter than the anterior ligament of the vertebral bodies. In a mathematical model of the spine it was demonstrated that-although the vertebral column in humans is still predominantly loaded in an axial direction-certain segments of the human spine (especially the backward inclined segments) are subject to dorsally directed shear loads as well. In addition to the antero-posterior difference in growth, there is also a deformation of the vertebral bodies itself in 3-D. This is probably secondary and not primary effects, but this question is still under discussion. For the treatment of scoliosis, the biomechanical principles of axial and transverse forces are used. The combination of axial and transverse loads is most beneficial for all curves. The axial forces provide most of the corrective bending moment when deformity is severe, while the transverse loads take over the correcting function when deformity is mild. The deformity angle of 53° is the break-even point for the axial and transverse loads. In more severe curves transverse forces become less and less efficient, while axial forces rapidly gain more and more effect.

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.

SNP rs11190870 near LBX1 is associated with adolescent idiopathic scoliosis in southern Chinese

A study was conducted to validate the most significant single nucleotide polymorphism (SNP) from a genome-wide association study of Japanese adolescent idiopathic scoliosis (AIS) patients in an independent southern Chinese population. In total, 300 AIS patients fulfilled the clinical criteria and 788 controls with MRI scans of the spine were included in the replication study. We employed case-control analysis to study the association of SNP rs11190870 near LBX1 (ladybird homeobox 1) with AIS in a southern Chinese population. The results suggest that SNP rs11190870 is significantly associated with AIS (P=9.1 × 10(-10); odds ratio=1.85; 95% confidence interval=1.52-2.25). The results of this study confirm that SNP rs11190870 is associated with AIS.

Genomic polymorphisms of G-protein estrogen receptor 1 are associated with severity of adolescent idiopathic scoliosis

PURPOSE

Adolescent idiopathic scoliosis (AIS) is reported to be associated with the two traditional estrogen receptor genes, ESR1 and ESR2. Yet, the novel estrogen receptor G protein-coupled estrogen receptor 1 (GPER) has not been studied. To investigate the association of GPER gene polymorphisms with the onset and deterioration of AIS, we performed a case-control study.

METHODS

Clinical information was recorded, blood samples were taken and genomic DNA was extracted. After resequencing the gene in 45 cases and 45 controls who were randomly selected, 16 tag single nucleotide polymorphisms (SNPs) were selected. Then the association study was extended by an additional 344 patients and 293 controls with direct sequencing and a TaqMan-based genotyping assay. The chi-square test and logistic regression were used to analyse the genotypic and allelic association. One-way analysis of variance was used to compare the mean maximum Cobb angles and ages with different genotypes in the case-only data set.

RESULTS

No association was observed between the polymorphisms of the GPER gene and susceptibility to AIS. However, heterozygotes in three SNPs of the gene (rs3808351, rs10269151 and rs426655s3) were related significantly with the curve severity in AIS patients (P = 0.004, 0.048 and 0.028, respectively).

CONCLUSIONS

Our results demonstrate that GPER gene polymorphisms are associated with the severity of curvature in AIS; deficits of GPER may contribute to the deterioration of spine deformity.

Differential proteome analysis of bone marrow mesenchymal stem cells from adolescent idiopathic scoliosis patients

Adolescent idiopathic scoliosis (AIS) is a complex three-dimensional deformity of the spine. The cause and pathogenesis of scoliosis and the accompanying generalized osteopenia remain unclear despite decades of extensive research. In this study, we utilized two-dimensional fluorescence difference gel electrophoresis (2D-DIGE) coupled with mass spectrometry (MS) to analyze the differential proteome of bone marrow mesenchymal stem cells (BM-MSCs) from AIS patients. In total, 41 significantly altered protein spots were detected, of which 34 spots were identified by MALDI-TOF/TOF analysis and found to represent 25 distinct gene products. Among these proteins, five related to bone growth and development, including pyruvate kinase M2, annexin A2, heat shock 27 kDa protein, γ-actin, and β-actin, were found to be dysregulated and therefore selected for further validation by Western blot analysis. At the protein level, our results supported the previous hypothesis that decreased osteogenic differentiation ability of MSCs is one of the mechanisms leading to osteopenia in AIS. In summary, we analyzed the differential BM-MSCs proteome of AIS patients for the first time, which may help to elucidate the underlying molecular mechanisms of bone loss in AIS and also increase understanding of the etiology and pathogenesis of AIS.

A major QTL controls susceptibility to spinal curvature in the curveback guppy

Background

Understanding the genetic basis of heritable spinal curvature would benefit medicine and aquaculture. Heritable spinal curvature among otherwise healthy children (i.e. Idiopathic Scoliosis and Scheuermann kyphosis) accounts for more than 80% of all spinal curvatures and imposes a substantial healthcare cost through bracing, hospitalizations, surgery, and chronic back pain. In aquaculture, the prevalence of heritable spinal curvature can reach as high as 80% of a stock, and thus imposes a substantial cost through production losses. The genetic basis of heritable spinal curvature is unknown and so the objective of this work is to identify quantitative trait loci (QTL) affecting heritable spinal curvature in the curveback guppy. Prior work with curveback has demonstrated phenotypic parallels to human idiopathic-type scoliosis, suggesting shared biological pathways for the deformity.

Results

A major effect QTL that acts in a recessive manner and accounts for curve susceptibility was detected in an initial mapping cross on LG 14. In a second cross, we confirmed this susceptibility locus and fine mapped it to a 5 cM region that explains 82.6% of the total phenotypic variance.

Conclusions

We identify a major QTL that controls susceptibility to curvature. This locus contains over 100 genes, including MTNR1B, a candidate gene for human idiopathic scoliosis. The identification of genes associated with heritable spinal curvature in the curveback guppy has the potential to elucidate the biological basis of spinal curvature among humans and economically important teleosts.

Association study of BMP4, IL6, Leptin, MMP3, and MTNR1B gene promoter polymorphisms and adolescent idiopathic scoliosis

STUDY DESIGN

a genetic association study was performed on 126 patients with adolescent idiopathic scoliosis and 197 healthy controls from independent Hungarian pedigrees.

OBJECTIVE

to reveal implication of promoter polymorphisms of bone morphogenetic protein 4 (BMP4), interleukin-6 (IL6), leptin, matrix metalloproteinase-3 (MMP3), melatonin 1B receptor (MTNR1B) genes in adolescent idiopathic scoliosis (AIS). Combinatorial association of these candidate genes was also studied to detect additive effect of certain single-nucleotide polymorphism (SNP) patterns.

SUMMARY OF BACKGROUND DATA

it was previously unraveled that IL6, MMP3, and MTNR1B genes could be considered as predisposition genes of AIS. Since BMP4 and leptin play a central role in bone formation and remodeling and are in direct interaction with melatonin, IL6, and MMP3, these also can be potential predisposition genes.

METHODS

the genotyping was determined by polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

at a single gene level, no significant differences were found for allele and genotype frequencies of the polymorphisms of these genes between cases or controls; therefore, the formerly detected association of IL6, MMP3, and MTNR1B with AIS was not confirmed in the Hungarian population by independent SNP analysis. However, significantly increased AIS risk was observed at particular combinations of genotypes of paired SNPs of the candidate genes.

CONCLUSIONS

the genetic effect of promoter polymorphisms of BMP4, IL6, leptin, MMP3, and MTNR1B can be synergistic for susceptibility to AIS. The combinatorial effect can modulate the final biological impact of many susceptibility polymorphisms; therefore, this should be considered at the comparison of results from case-control studies of different populations.

Concordance for curve type in familial idiopathic scoliosis: a survey of one hundred families

STUDY DESIGN

Prospective comparative study on 100 patients with positive family history for idiopathic scoliosis.

OBJECTIVE

To evaluate the concordance rate for curve pattern and side in family members with idiopathic scoliosis.

SUMMARY OF BACKGROUND DATA

The pathogenesis of idiopathic scoliosis has been the subject of extensive research. It is termed multifactorial with a genetic component. Similar curve shape has been reported in twins with idiopathic scoliosis.

METHODS

We included prospectively 100 patients with idiopathic scoliosis when a relative of them was also affected with idiopathic scoliosis, and spine radiographs were available for both. Concordance for curve pattern by Lenke classification and side between family members was analyzed.

RESULTS

Familial concordance rate for curve pattern and side was 66% (95% confidence interval, 57-75), whereas the expected random concordance rate was 26% (95% confidence interval, 17-34). The affected relative was in 27 cases a sibling, in 32 cases a parent, in 1 case an uncle, in 2 cases a cousin, in 2 cases a half sister, in 2 cases a grandmother. Concordance rate was 65% (27/42) in siblings' pairs and 67% (32/48) in parents/child's pairs.

CONCLUSION

We report a high concordance rate for curve pattern and side between relatives with idiopathic scoliosis. Curve shape is likely to be genetically determined in familial scoliosis. It seems important that curve type is documented and considered in future genetic studies.

Vestibular asymmetry as the cause of idiopathic scoliosis: a possible answer from Xenopus

Human idiopathic scoliosis is characterized by severe deformations of the spine and skeleton. The occurrence of vestibular-related deficits in these patients is well established but it is unclear whether a vestibular pathology is the common cause for the scoliotic syndrome and the gaze/posture deficits or if the latter behavioral deficits are a consequence of the scoliotic deformations. A possible vestibular origin was tested in the frog Xenopus laevis by unilateral removal of the labyrinthine endorgans at larval stages. After metamorphosis into young adult frogs, X-ray images and three-dimensional reconstructed micro-computer tomographic scans of the skeleton showed deformations similar to those of scoliotic patients. The skeletal distortions consisted of a curvature of the spine in the frontal and sagittal plane, a transverse rotation along the body axis and substantial deformations of all vertebrae. In terrestrial vertebrates, the initial postural syndrome after unilateral labyrinthectomy recovers over time and requires body weight-supporting limb proprioceptive information. In an aquatic environment, however, this information is absent. Hence, the lesion-induced asymmetric activity in descending spinal pathways and the resulting asymmetric muscular tonus persists. As a consequence the mostly cartilaginous skeleton of the frog tadpoles progressively deforms. Lack of limb proprioceptive signals in an aquatic environment is thus the element, which links the Xenopus model with human scoliosis because a comparable situation occurs during gestation in utero. A permanently imbalanced activity in descending locomotor/posture control pathways might be the common origin for the observed structural and behavioral deficits in humans as in the different animal models of scoliosis.

Using a synthesis of the research literature related to the aetiology of adolescent idiopathic scoliosis to provide ideas on future directions for success

This review is atypical by design. It has used a synthesis of the available literature relating to the aetiology of AIS to draw attention to the lack of progress in this area despite intensive research for more than 100 years. The review has argued that if progress is to be made in this area then significant changes in approach to the problem must be made. Such changes have been outlined and major areas of potential focus identified with the intention of creating debate and discussion. There is no doubt that people are working hard in this area of research but this review has deliberately attempted to question its achievements and future directions.

"It is not enough to be busy, so are the ants. The question is what are you so busy about.'

Walden – Henry David Thoreau