Histomorphological study of the spinal growth plates from the convex side and the concave side in adolescent idiopathic scoliosis

The role of scoliosis on temporomandibular joint disease: a cross-sectional study based on ultrasonography

AIM

To investigate the relationship between temporomandibular disorders (TMD) and the stomatognathic system and spine through a multidisciplinary approach, utilising ultrasound to assess the temporomandibular joint.

MATERIALS AND METHODS

Between October 2020 and January 2021, 50 patients aged 12-18 years with adolescent idiopathic scoliosis and 50 healthy individuals were enrolled. All participants underwent clinical examinations based on the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) protocol. Additionally, ultrasound evaluations were performed of the temporomandibular joint and masseter muscles. Subsequently, the data from both groups were compared and analysed.

RESULTS

The mean age of participants was 14.69 ± 2.73 years in the scoliosis group (SG) and 14.68 ± 1.81 years in the control group (CG). Among scoliosis patients, a moderate negative correlation was observed between the Cobb angle (indicative of curvature severity) and mouth opening (p=0.023; r=-0.320). Furthermore, the incidence of TMD was significantly higher in the scoliosis group compared to the control group (p<0.001). Additionally, it was found that a 1-unit increase in joint space elastography value led to a 4.81-fold higher likelihood of diagnosing disc displacement with reduction (p=0.009; 95% CI: 1.47-15.73).

CONCLUSION

This pioneering study, the first of its kind to explore the connection between scoliosis and ultrasound-based temporomandibular joint screening, suggests that scoliosis may be a predisposing factor for TMD. Moreover, the present findings underscore the importance of joint elastography as a valuable quantitative tool in TMD diagnosis.

Novel dual: rod plate system for EOS improves vertebral wedging and permits spinal growth

BACKGROUND

To determine whether single-stage, growth-friendly instrumentation with a plate-rod spinal system (PRSS) can substantially correct the deformity of EOS at surgery and continue to rectify the deformity throughout the growth period.

METHODS

An observational study of 35 children with EOS treated by PRSS between February 2000 and October 2010 during a mean follow-up of 72 months. The mean age at surgery was 7 years. X-rays were taken preoperatively and postoperatively and at each follow-up. The Cobb angle, the apical vertebral wedge angle (AVWA), remaining rod lengths, maximal thoracic kyphosis and total T1-S1 heights were measured and compared.

RESULTS

Thirty-one patients, 9 boys and 22 girls, with a mean age of 7 years were completed follow-up. The Cobb angle changed from 64° to 36° after initial surgery and 26° at the last follow-up. The mean AVWA was 15° postoperatively and 5° at the last follow-up. The mean rod tail reserve length decreased from 53 mm immediately after surgery to 12 mm at the last follow-up. The mean preoperative maximum thoracic kyphosis was 41° and changed to 35° and 30° postoperatively and at latest follow-up, respectively. The mean preoperative T1-S1 height for all 32 patients was 52 mm acute lengthening and 122 mm of lengthening by the end of follow-up, respectively.

CONCLUSION

The PRSS provided immediate correction of most of the deformity at surgery and continued to rectify remaining scoliosis during the growth period. AVWA may be a useful method for monitoring the function of the PRSS in EOS.

Compressive stress induces spinal vertebral growth plate chondrocytes apoptosis via Piezo1

Many clinical studies have indicated an association between biomechanical factors and the incidence and pathological progression of adolescent idiopathic scoliosis (AIS). However, at present, the research on AIS is mainly focused on the etiology, and there are few studies reporting the causes of progressive aggravation of AIS. In the present study, we aim to investigate the role of Piezo1 in compressive stress-induced mouse spinal vertebral growth plate chondrocytes apoptosis. First, a scoliosis mouse model was established, and the expression of Piezo1 as well as the degree of apoptosis were investigated. We found that the expression of Piezo1 and the degree of apoptosis were significantly higher on the concave sides than that on the convex sides of the vertebral growth plate in mice with scoliosis. Spinal vertebral growth plate chondrocytes were further isolated and treated with Yoda1 to mimic Piezo1 overload. Excess Piezo1 significantly promoted apoptosis of spinal vertebral growth plate chondrocytes. Moreover, static gas compressive stress was used to simulate the increased concave compressive stress in the process of scoliosis with or without GsMTx4, a Piezo inhibitor. It was observed that with the increase of static compressive stress, the expression of Piezo1 increased, and the chondrocytes of vertebral growth plate treated with Piezo1 inhibitor GsMTx4 weakened the above phenomena. In conclusion, our results indicated that compressive stress is strongly associated with the different degrees of apoptosis on both sides on the convex and concave sides of the vertebral growth plate in scoliosis via inducing different expressions of Piezo1. Reducing the expression of Piezo1 in the concave side of the vertebral growth plate and inhibiting the apoptosis of chondrocytes in the bilateral vertebral growth plate caused by asymmetric stress on both sides of the concave vertebral body may be a promising treatment strategy for AIS.

Lower androgen levels promote abnormal cartilage development in female patients with adolescent idiopathic scoliosis

Background

Adolescent idiopathic scoliosis (AIS) is a disease characterized by changes in the three-dimensional structure of the spine. Studies have shown that the development of AIS might be associated with genetic, biomechanics, endocrine factors and abnormal bone or cartilage development.

Methods

Blood samples collected from 301 female patients (161 females with AIS and 140 females without AIS) were used for genotyping. Forty-eight serum samples from 161 females with AIS and 40 serum samples from 140 females without AIS were subjected to enzyme-linked immunosorbent assays (ELISAs). We also evaluated 32 facet joints (18 females with AIS and 14 females without AIS from the 301 female patients) using immunohistochemistry, Western blotting, and isolation of human primary chondrocytes, among other methods. We treated the AIS primary chondrocytes with dihydrotestosterone (DHT) to verify the relationship among androgen, the androgen receptor (AR), and its downstream pathway proteins.

Results

The serum androgen level in the AIS group was significantly decreased (1.94±0.09 vs. 2.284±0.103) compared with that in the non-AIS (control) group. The single nucleotide polymorphism genotyping results showed that the mutation rates of rs6259 between the AIS and control groups were significantly different (G/G genotype: 48.4% vs. 42.1%, G/A genotype: 40.4% vs. 35.7%, P<0.05). The levels of interleukin (IL)-6 and metalloproteinase (MMP)-13 were increased in the cartilage of AIS patients, and these patients also exhibited decreased AR levels. The cell experiment results showed that androgen reduced the degree of abnormal cartilage development in female AIS patients through the AR/IL-6/signal transducer and activator of transcription 3 (STAT3) signaling pathway.

Conclusions

Our study provides a new perspective on the pathogenesis of AIS and indicates that decreased androgen levels in female AIS patients play a potential role in the development of AIS via the AR/IL-6/STAT3 signaling pathway.

Dysregulation of the ghrelin/RANKL/OPG pathway in bone mass is related to AIS osteopenia

BACKGROUND

Osteopenia has been well documented in adolescent idiopathic scoliosis (AIS), and ghrelin has been shown to have a positive effect on bone metabolism. However, the circulating level of ghrelin is increased in AIS osteopenia, and the relationship between ghrelin and low bone mass in AIS osteopenia remains unclear.

METHOD

A total of 563 AIS and 281 age-matched controls were recruited for this study. Anthropometry and bone mass were measured in all participants. Plasma ghrelin levels were determined by enzyme-linked immunosorbent assay (ELISA) in both AIS and control groups. An improved multiplex ligation detection reaction was performed to analyze single-nucleotide polymorphisms (SNPs). Facet joints were collected and subjected to immunohistochemistry; osteogenic gene and protein expression was also measured. Furthermore, primary cells were extracted from facet joints and bone marrow to observe the response to ghrelin stimulation.

RESULTS

The body mass index was lower and circulating ghrelin was markedly higher in the AIS osteopenia group than in the control group. No significant difference was observed in four ghrelin level-related SNPs between the AIS osteopenia and control groups. RNA and protein analyses revealed higher RANKL/OPG and lower runx2 levels in AIS cancellous bone. Compared with normal primary osteoblasts and BMSCs, AIS osteopenia primary cells were insensitive to the same ghrelin concentration gradient and showed lower osteogenic ability, increases in OPG and decreases in RANKL.

CONCLUSION

Our results indicate that high circulating ghrelin levels may not result from gene variations in AIS osteopenia. Dysregulation of the ghrelin/RANKL/OPG pathway may lead to decreased osteogenic ability of osteoblasts and BMSCs, which may be related to lower bone mass in AIS osteopenia.

Evaluation of choroidal changes in adolescent idiopathic scoliosis using enhanced depth imaging optical coherence tomography

BACKGROUND

We aimed to evaluate the choroidal thickness (CT) in patients with adolescent idiopathic scoliosis (AIS) using enhanced depth imaging optical coherence tomography (EDI-OCT).

METHODS

In this cross-sectional, observational comparative study, 56 eyes of 56 patients with AIS and 56 eyes of 56 age- and sex-matched healthy subjects were included. All participants underwent complete ophthalmologic examination and CT measurements at the fovea and at 750 μm intervals from the fovea to 1,500 μm in the nasal and temporal site obtained by spectral domain EDI-OCT.

RESULTS

The mean subfoveal CT was lower in the AIS patients (285.2 ± 24.4 μm) than that of the controls (313.2 ± 28.8 μm; p < 0.001). The difference was also significant at all extrafoveal measurement points (p < 0.001 for all). There were negative correlations of CTs at subfoveal and extrafoveal locations with the Cobb's angle in the AIS patients (for subfoveal location: r = -0.71 and p < 0.001; and for extrafoveal locations: r = -0.66 and p < 0.001 at 750 μm in the nasal side; r = -0.64 and p < 0.001 at 1,500 μm in the nasal side; r = -0.71 and p < 0.001 at 750 μm in the temporal side; and r = -0.69 and p < 0.001 at 1,500 μm in the temporal side).

CONCLUSION

This preliminary study showed that AIS patients have thinner CT compared to that of healthy subjects. The lower CT was correlated with the increased angle of scoliosis.

Adiponectin regulates bone mass in AIS osteopenia via RANKL/OPG and IL6 pathway

BACKGROUND

Osteopenia have been well documented in adolescent idiopathic scoliosis (AIS). Adiponectin has been shown to be inversely proportional to body mass index and to affect bone metabolism. However, the circulating levels of adiponectin and the relationship between adiponectin and low bone mass in AIS remain unclear.

METHODS

A total of 563 AIS and 281 age-matched controls were recruited for this study. Anthropometry and bone mass were measured in all participants. Plasma adiponectin levels were determined by enzyme-linked immunosorbent assay (ELISA) in the AIS and control groups. An improved multiplex ligation detection reaction was performed to study on single nucleotide polymorphism. Facet joints were collected and used to measure the microstructure, the expression of RANKL, OPG, osteoblast-related genes, inflammatory factors, adiponectin and its receptors by qPCR, western blotting and immunohistochemistry. Furthermore, primary cells were extracted from facet joints to observe the reaction after adiponectin stimulation.

RESULTS

Compared with the controls, lower body mass index and a marked increase in circulating adiponectin were observed in AIS osteopenia (17.09 ± 1.09 kg/m² and 21.63 ± 10.30 mg/L). A significant difference in the presence of rs7639352
was detected in the AIS osteopenia, AIS normal bone mass and control groups. The T allele showed a significant higher proportion in AIS osteopenia than AIS normal bone mass and control groups (41.75% vs 31.3% vs 25.7%, p < 0.05). micro-CT demonstrated that the AIS convex side had a significant lower bone volume than concave side. RNA and protein analyses showed that in cancellous bone, higher RANKL/OPG and adipoR1 levels and lower runx2 levels were observed, and in cartilage, higher adipoR1 and IL6 levels were observed in AIS. Furthermore, convex side had higher RANKL/OPG, IL6 and adipoR1 than concave side. Compared with normal primary cells, convex side primary cells showed the most acute action, and concave side primary cells showed the second-most acute action when exposed under same adiponectin concentration gradient.

CONCLUSION

Our results indicated that high circulating adiponectin levels may result from gene variations in AIS osteopenia. Adiponectin has a negative effect on bone metabolism, and this negative effect might be mediated by the ADR1-RANKL/OPG and ADR1-IL6 pathways.

Scoliosis vertebral growth plate histomorphometry: Comparisons to controls, growth rates, and compressive stresses

Scoliosis progression in skeletally immature patients depends on remaining growth. Relationships between vertebral growth plate histomorphometry, growth rates, and mechanical stresses have been reported in several animal studies. Hypertrophic zone heights and chondrocyte heights have been used to assess treatments that aim to modulate growth. The purpose of this study was to determine whether human vertebral physeal hypertrophic zone and cell heights differed between two groups: Severe scoliosis and autopsy controls. Severity was defined at time of surgical planning by curve magnitude and curve stiffness. Physeal samples were obtained from the convex side apex, and from the concave side when feasible. Histologic sections were prepared, and digital images were used to measure hypertrophic zone height, cell height, and cell width. Thirteen spinal deformity patients were included, mean curve magnitude 67° (±23). Etiologies were juvenile and adolescent idiopathic, congenital, neurofibromatosis, neuromuscular, and Marfan syndrome. Five age-matched autopsy specimens without scoliosis served as controls. Results were presented by etiology, then all convex scoliosis specimens were combined and compared to controls. Zone heights for scoliosis, convex side, and controls were 152 µm (±34) and 180 µm (±42) (p = 0.21), cell heights 8.5 µm (±1.1) and 12.8 µm (±1.2) (p < 0.0005), and cell widths 14.9 µm (±1.5) and 15.0 µm (±2.5), respectively. Human values were compared to published animal models and to a quantitative theory of a stress ̶ growth curve. This quantification of vertebral physeal structures in scoliosis may be expected to help assess theories of progression and potential treatments using growth modulation. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2450-2459, 2018.

Abnormal PITX1 gene methylation in adolescent idiopathic scoliosis: a pilot study

Background

The gene of pituitary homeobox 1 (PITX1) has been reported to be down-regulated in adolescent idiopathic scoliosis (AIS), of which the cause has not been well addressed. The abnormal DNA methylation was recently assumed to be an important mechanism for the down-regulated genes expression. However, the association between PITX1 promoter methylation and the etiology of AIS was not clear.

Methods

The peripheral blood samples of 50 AIS patients and 50 healthy controls were collected and the genomic DNA was extracted. The pyrosequencing assay was used to assess the methylation status of PITX1 promoter and real-time quantitative polymerase chain reaction (PCR) was used to detect the PITX1 gene expression. Comparison analysis was performed using independent t test and Chi-square tests, while correlation analysis were performed with 2-tailed Pearson coefficients.

Results

The mean methylation level was (3.52 ± 0.96)% in AIS and (1.40 ± 0.81)% in healthy controls (P < 0.0001). The PITX1 gene expression was 0.15 ± 0.08 in AIS and 0.80 ± 0.55 in healthy controls (P < 0.0001). The comparative analysis showed significant difference in age (P = 0.021) and Cobb angle of the main curve (P = 0.0001) between AIS groups with positive and negative methylation. The methylation level of 6 CpG sites in PITX1 promoters was significantly associated with Cobb angle of the main curve (P < 0.001) in AIS. No statistical relationship between PITX1 promoter methylation and gene expression was found in AIS (P = 0.842).

Conclusion

Significantly higher methylation level and lower PITX1 gene expression are found in AIS patients. PITX1 methylation is associated with Cobb angles of the main curves in AIS. DNA methylation thus plays an important role in the etiology and curve progression in AIS.

Plasticity of vertebral wedge deformities in skeletally immature patients with adolescent idiopathic scoliosis after posterior corrective surgery

Background

Vertebral bodies in patients with adolescent idiopathic scoliosis (AIS) usually have frontal wedge deformities. However, the plasticity of the deformed vertebrae in skeletally immature patients is unknown. The purpose of our study was to clarify the plasticity of vertebral deformities in skeletally immature patients with AIS by using in vivo three-dimensional (3D) analysis.

Methods

Ten female patients with AIS (mean age, 12.2 years; three patients, Lenke type 1; five patients, type 2; two patients, type 5) who underwent posterior fusion and whose Risser grade was ≤3 at surgery were included. Using computed tomography images (0.625-mm slice thickness) obtained 1 week and 1 year postoperatively, a total of seventy-three 3D bone models of vertebrae was made. The 3D bone models were made between the upper and lower end vertebrae within the main thoracic curve for patients with Lenke types 1 and 2 scoliosis, whereas they were made within the thoracolumbar/lumbar curve in patients with Lenke type 5 scoliosis. The height of the concave and convex sides in the anterior, middle and posterior parts of the vertebral bodies was measured using the original digital viewer, and the vertebral height ratio (VHR: concave/convex) was calculated. VHRs at 1 week and 1 year postoperatively were compared using the Wilcoxson signed-rank test. Differences were considered statistically significant at p < 0.05.

Results

VHR of the end vertebrae (n = 20) did not change postoperatively for any parts of the vertebral bodies. VHR of the vertebrae in the apical region (n = 28) also remained unchanged postoperatively. In contrast, VHR of the other vertebrae (n = 25) increased significantly in the anterior part postoperatively (from 0.938 to 0.961, p = 0.006).

Conclusions

The wedge deformity of vertebral bodies showed a reshaping potential towards a symmetrical configuration in the region other than end and apex, although no plasticity of the vertebrae was observed in the apical region even in skeletally immature patients with AIS.

Accurate prediction of height loss in adolescent idiopathic scoliosis: Cobb angle alone is insufficient

PURPOSE

Spinal height loss due to scoliosis was mostly calculated by equations with Cobb angle as the unique independent variable in adolescent idiopathic scoliosis (AIS), with their accuracy being seriously doubted. The purpose of this study was to compare and correlate the measured loss in spinal height (ΔSHm) with the calculated loss in spinal height (ΔSHc), and to identify the key factors associated with height loss in AIS.

METHODS

This retrospective study included two stages. In stage I, 277 surgically treated AIS patients were reviewed, and divided into single curve and double curve groups. The accuracy and limitation of each correction equation was testified by comparing the data sets of ΔSHc with the ΔSHm, as well as comparing the pre- and post-op spinal length for each correction equation. In stage II, 235 curves within 100 AIS patients were selected to explore the relationship between loss in vertical curve height (△CH) and Cobb angle, curve length (CL), number of vertebrae within the curve (NVC), tilt angle of each curve (α) through partial correlation analysis.

RESULTS

In stage I, the △SHm averaged 3.5 cm in single curve group and 4.8 cm in double curve group. The ΔSHc was only comparable with ΔSHm using the Bjure's equation. Pre- and post-op spinal length was only comparable in Bjure's corrected group with Cobb angle <60° (p > 0.05). In stage II, the partial correlation coefficients of △CH with Cobb angle, CL, α, and NVC were 0.889, 0.493, -0.723 and -0.175 (p < 0.01), respectively. The △CH could be calculated by the following formula: △CH (mm) = 29.305 + 0.506Cobb + 0.083CL - 0.592α - 0.796NVC.

CONCLUSIONS

Previous height correction equations employing Cobb angle as the unique independent variable are inaccurate. Cobb angle, curve length, curve inclination, and number of vertebrae within the curve are all strong determinants responsible for the height loss in AIS.

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.

Effects of mechanical loading on the expression of pleiotrophin and its receptor protein tyrosine phosphatase beta/zeta in a rat spinal deformity model

Mechanical loading of the spine is a major causative factor of degenerative changes and causes molecular and structural changes in the intervertebral disc (IVD) and the vertebrae end plate (EP). Pleiotrophin (PTN) is a growth factor with a putative role in bone remodeling through its receptor protein tyrosine phosphatase beta/zeta (RPTPβ/ζ). The present study investigates the effects of strain on PTN and RPTPβ/ζ protein expression in vivo. Tails of eight weeks old Sprague-Dawley rats were subjected to mechanical loading using a mini Ilizarov external apparatus. Rat tails untreated (control) or after 0 degrees of compression and 10°, 30° and 50° of angulation (groups 0, I, II and III respectively) were studied. PTN and RPTPβ/ζ expression were evaluated using immunohistochemistry and Western blot analysis. In the control group, PTN was mostly expressed by the EP hypertrophic chondrocytes. In groups 0 to II, PTN expression was increased in the chondrocytes of hypertrophic and proliferating zones, as well as in osteocytes and osteoblast-like cells of the ossification zone. In group III, only limited PTN expression was observed in osteocytes. RPTPβ/ζ expression was increased mainly in group 0, but also in group I, in all types of cells. Low intensity RPTPβ/ζ immunostaining was observed in groups II and III. Collectively, PTN and RPTPβ/ζ are expressed in spinal deformities caused by mechanical loading, and their expression depends on the type and severity of the applied strain.

Genome-wide association study identifies new susceptibility loci for adolescent idiopathic scoliosis in Chinese girls

Adolescent idiopathic scoliosis (AIS) is a structural deformity of the spine affecting millions of children. As a complex disease, the genetic aetiology of AIS remains obscure. Here we report the results of a four-stage genome-wide association study (GWAS) conducted in a sample of 4,317 AIS patients and 6,016 controls. Overall, we identify three new susceptibility loci at 1p36.32 near AJAP1 (rs241215, P_combined=2.95 × 10⁻⁹), 2q36.1 between PAX3 and EPHA4 (rs13398147, P_combined=7.59 × 10⁻¹³) and 18q21.33 near BCL-2 (rs4940576, P_combined=2.22 × 10⁻¹²). In addition, we refine a previously reported region associated with AIS at 10q24.32 (rs678741, P_combined=9.68 × 10⁻³⁷), which suggests LBX1AS1, encoding an antisense transcript of LBX1, might be a functional variant of AIS. This is the first GWAS investigating genetic variants associated with AIS in Chinese population, and the findings provide new insight into the multiple aetiological mechanisms of AIS.

The authors perform a genome-wide association study of adolescent idiopathic scoliosis patients of Han Chinese descent, and identify 3 new loci for disease susceptibility.

The use of non-adult vertebral dimensions as indicators of growth disruption and non-specific health stress in skeletal populations

OBJECTIVE

Traditional methods of detecting growth disruption have focused on deficiencies in the diaphyseal length of the long bones. This study proposes the implementation of vertebral measurements (body height and transverse diameter of the neural canal) from non-adults (0-17 years) as a new methodology for the identification of growth disruption.

METHODS

Measurements of vertebral body height and transverse diameter were taken from 96 non-adult skeletons and 40 adult skeletons from two post-medieval sites in England (Bow Baptist, London and Coronation Street, South Shields). Non-adult measurements were plotted against dental age to construct vertebral growth profiles through which inter-population comparisons could be made.

RESULTS

Results demonstrated that both sites experienced some growth retardation in infancy, evident as deficiencies in transverse diameter. However, analysis of vertebral body height revealed different chronologies of growth disruption between the sites, with a later age of attainment of skeletal maturity recorded in the Bow Baptist sample.

DISCUSSION

These vertebral dimensions undergo cessation of growth at different ages, with transverse diameter being "locked-in" by ∼1-2 years of age, while vertebral body height may continue to grow into early adulthood. These measurements can therefore provide complementary information regarding the timing of growth disruption within archaeological populations. Non-adult vertebral measurements can increase our osteobiographical understanding of the timings of episodes of health stress, and allow for the analysis of growth when other skeletal elements are fragmentary.

Glucagon-like peptide-2-loaded microspheres as treatment for ulcerative colitis in the murine model

Glucagon-like peptide-2 (GLP-2) is an intestinal hormone that promotes intestinal growth, but the rapid degradation by dipeptidyl peptidase-IV limits its applications. PLGA microsphere is a well-developed drug delivery system, while seldom been studied as a solution for prolonging in vivo effects of GLP-2. In this study, we encapsulated porcine GLP-2 (pGLP-2) into microspheres and investigated its therapeutic effects in dextran sulfate sodium (DSS)-treated mice. pGLP-2 microspheres showed 20.36% in initial burst and constant release for at least 9 d. In the DSS-treated mice, a single injection of GLP-2 microspheres significantly increased the body weight, colonic length, small intestinal weight and mRNA expression of Occludin, decreased the colonic damage score, mRNA expression of IL-6, IL-10, TNF-α and IFN-γ. In conclusion, pGLP-2 microspheres were resistant to degradation and decreased the severity of DSS-induced ulcerative colitis which suggested that GLP-2-loaded microspheres could be a proper candidate for the treatment of ulcerative colitis.

Ultrastructure of Intervertebral Disc and Vertebra-Disc Junctions Zones as a Link in Etiopathogenesis of Idiopathic Scoliosis

Background Context. There is no general accepted theory on the etiology of idiopathic scoliosis (IS). An important role of the vertebrae endplate physes (VEPh) and intervertebral discs (IVD) in spinal curve progression is acknowledged, but ultrastructural mechanisms are not well understood. Purpose. To analyze the current literature on ultrastructural characteristics of VEPh and IVD in the context of IS etiology. Study Design/Setting. A literature review. Results. There is strong evidence for multifactorial etiology of IS. Early wedging of vertebra bodies is likely due to laterally directed appositional bone growth at the concave side, caused by a combination of increased cell proliferation at the vertebrae endplate and altered mechanical properties of the outer annulus fibrosus of the adjacent IVD. Genetic defects in bending proteins necessary for IVD lamellar organization underlie altered mechanical properties. Asymmetrical ligaments, muscular stretch, and spine instability may also play roles in curve formation. Conclusions. Development of a reliable, cost effective method for identifying patients at high risk for curve progression is needed and could lead to a paradigm shift in treatment options. Unnecessary anxiety, bracing, and radiation could potentially be minimized and high risk patient could receive surgery earlier, rendering better outcomes with fewer fused segments needed to mitigate curve progression.

Animal models for scoliosis research: state of the art, current concepts and future perspective applications

PURPOSE

The purpose of this study was to provide the readers with a reliable source of animal models currently being utilized to perform state-of-the-art scoliotic research.

MATERIALS AND METHODS

A comprehensive search was undertaken to review all publications on animal models for the study of scoliosis within the database from 1946 to January 2011.

RESULTS

The animal models have been grouped under specific headings reflecting the underlying pathophysiology behind the development of the spinal deformities produced in the animals: genetics, neuroendocrine, neuromuscular, external constraints, internal constraints with or without tissue injury, vertebral growth modulation and iatrogenic congenital malformations, in an attempt to organize and classify these multiple scoliotic animal models. As it stands, there are no animal models that mimic the human spinal anatomy with all its constraints and weaknesses, which puts it at risk of developing scoliosis. What we do have are a multitude of models, which produce spinal deformities that come close to the idiopathic scoliosis deformity.

CONCLUSION

All these different animal models compel us to believe that the clinical phenotype of what we call idiopathic scoliosis may well be caused by a variety of different underlying pathologies.

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.

Expression of matrix metalloproteinase-1 (MMP-1) in Wistar rat's intervertebral disc after experimentally induced scoliotic deformity

Introduction

A scoliotic deformity on intervertebral discs may accelerate degeneration at a molecular level with the production of metalloproteinases (MMPs). In the present experimental study we evaluated the presence of MMP-1 immunohistochemically after application of asymmetric forces in a rat intervertebral disc and the impact of the degree of the deformity on MMP-1 expression.

Material-Method

Thirty female Wistar rats (aged 2 months old, weighted 200 ± 10 grams) were used. All animals were age, weight and height matched. A mini Ilizarov external fixator was applied at the base of a rat tail under anaesthesia in order to create a scoliotic deformity of the intervertebral disc between the 9^th and 10^th vertebrae. Rats were divided into three groups according to the degree of the deformity. In group I, the deformity was 10°, in group II 30° and in group III 50°. The rats were killed 35 days after surgery. The discs were removed along with the neighbouring vertebral bodies, prepared histologically and stained immunohistochemically. Immunopositivity of disc's cells for MMP-1 was determined using a semi-quantitative scored system.

Results

MMP-1 immunopositivity was detected in disc cells of annulus fibrosus of all intervertebral disc specimens examined. The percentage of MMP-1 positive disc cells in annulus fibrosus in group I, II and III were 20%, 43% and 75%, respectively. MMP-1 positivity was significantly correlated with the degree of the deformity (p < 0,001). An increase of chondrocyte-like disc cells was observed in the outer annulus fibrosus and at the margin of the intervertebral disc adjacent to the vertebral end plates. The difference in the proportion of MMP-1 positive disc cells between the convex and the concave side was statistically not significant in group I (p = 0,6), in group II this difference was statistically significant (p < 0,01). In group III the concave side showed a remarkable reduction in the number of disc's cells and a severe degeneration of matrix microstructure.

Conclusion

The present study showed that an experimentally induced scoliotic deformity on a rat tail intervertebral disc results in over-expression of MMP-1, which is dependent on the degree of the deformity and follows a dissimilar distribution between the convex and the concave side.

Effectiveness and outcomes of brace treatment: a systematic review

Bracing has been widely used for the treatment of adolescent idiopathic scoliosis (AIS). However, effectiveness of brace treatment remains controversial. A systematic review was conducted to investigate evidence that brace treatment is effective in the treatment of AIS. A total of 20 studies, including randomized controlled trials, nonrandomized clinical controlled trials, or case-control studies, were included. Studies comparing the results of brace treatment with no-treatment, other conservative treatments, or surgical treatment were included. Outcomes of the studies included radiological curve progression, incidence of surgery, pulmonary function, quality of life (QOL), and psychological state. The results from the systematic review are difficult to interpret. There are quite a number of varying parameters between studies that make it very difficult to reach any firm conclusions. In addition, the quality of evidence is limited because most of the studies included in this review were of low methodological quality. However, the available data suggest that, compared to observation, bracing is more potent in preventing the progression of scoliosis and may not have a negative impact on patients' QOL. Therefore, bracing can be recommended for the treatment of AIS, at least for female patients with a Cobb angle of 25-35°. Compared to other conservative treatments, bracing seems to be more effective than electrical stimulation, although an advantage of bracing over side-shift exercise or casting has not been established. Comparison between bracing and surgery is difficult because in most studies, the curve magnitude at baseline was considerably larger in the surgery group. We recommend that future studies have clearer and more consistent guidelines.

Remodelling of vertebral endplate subchondral bone in scoliosis: a micro-CT analysis in a porcine model

BACKGROUND

Disc degeneration has been correlated with alteration of bone density of adjacent vertebral bodies. Abnormal mechanical loading appears in scoliosis as compared to normal spines. How vertebral endplate was remodelled in scoliosis is not well understood.

METHODS

We conducted a micro-CT analysis of subchondral bone of the vertebral endplate at the curve apex in a porcine scoliosis model. Two adjacent thoracic T(5)-T(6) and lumbar L(1)-L(2) levels were instrumented in six four-week-old pigs with a custom offset implant connected by a flexible stainless steel wire. Two months after implantation, three cylindrical specimens were harvested into the vertebral endplate of each of the scoliosis levels: centre, convexity and concavity, and from the dorsal T(9)-T(10) vertebral units obtained from nine three-month-old non-instrumented pigs used as controls. Micro-CT analysis was carried out on each specimen.

FINDINGS

In the concavity of the scoliotic spine, bone volume fraction, trabecular thickness, and trabecular separation significantly increased whereas in the convexity, only trabecular separation increased. Connectivity index and trabecular number decreased significantly.

INTERPRETATION

This was the first micro-CT study of subchondral bone microarchitecture of the scoliotic vertebral end plate. At the curve apex, increased compression in the concavity induced an osteogenic process. In the convexity, diminished compression caused an osteolytic process with a local resorption. Clinically, the unbalanced tissue remodelling could play a role in the convective and diffusive transports into the end plate, which is of prime importance for the segment homeostasis in scoliosis treatment with or without surgery.

Expression of Runx2 and type X collagen in vertebral growth plate of patients with adolescent idiopathic scoliosis

The different expression of type X collagen and Runx2 between the convex and concave side of vertebral growth plate in scoliosis may help to improve our understanding of the role that growth plate tissue play in the development or progression of idiopathic scoliosis. In this investigation, there were significant differences of the total expression of type X collagen, Runx2 protein, and Runx2 mRNA between convex side and concave side growth plates of the apex vertebrae (p < 0.05). The total expression of type X collagen in the concave side growth plates of the lower end vertebrae was higher than that in the same side growth plates of apex (p < 0.05). The total expression of Runx2 in the concave side growth plates in the upper and lower end vertebrae were higher than that in the concave side growth plates of apex (p < 0.05). The expression of type X collagen, Runx2, and Runx2 mRNA, the cell density of type X collagen and Runx2 positive chondrocytes, and histological changes between convex side and concave side of the vertebral growth plate indicated that the vertebral growth plate was affected by mechanical forces, which was a secondary change and could contribute to progression of adolescent idiopathic scoliosis.

Epiphyseal fusion in the human growth plate does not involve classical apoptosis

By the end of puberty, growth ceases and epiphyseal fusion occurs through mechanisms not yet completely understood. Human growth plate tissues were collected in various pubertal stages including a unique late pubertal growth plate, which was about to fuse. Apoptosis was studied by TUNEL staining, immunolocalization of pro- and antiapoptotic proteins, and electron microscopy (EM). Morphologic analyses of the fusing growth plate revealed disorganized, large chondrocytes surrounded by a border of dense, cortical-like bone. In the unfused growth plates, few chondrocytes were TUNEL positive. In contrast, the fusing growth plate contained no single TUNEL-positive cell. Antiapoptotic (Bcl-2 and Bcl-XL) and proapoptotic (Bax, Bad, and cleaved caspase-3) proteins were detected in all growth plate zones without change in intensity during pubertal progression. Expression of antiapoptotic proteins was found in the fusing growth plate but of the proapoptotic proteins only Bad was detected. EM revealed no typical signs of apoptosis or autophagy in any of the growth plates. In contrast, morpohological signs of hypoxia and necrosis were observed. We conclude that classical apoptosis is not likely to be involved in the process of human growth plate fusion.

Pathogenesis of adolescent idiopathic scoliosis in girls - a double neuro-osseous theory involving disharmony between two nervous systems, somatic and autonomic expressed in the spine and trunk: possible dependency on sympathetic nervous system and hormones with implications for medical therapy

Anthropometric data from three groups of adolescent girls - preoperative adolescent idiopathic scoliosis (AIS), screened for scoliosis and normals were analysed by comparing skeletal data between higher and lower body mass index subsets. Unexpected findings for each of skeletal maturation, asymmetries and overgrowth are not explained by prevailing theories of AIS pathogenesis. A speculative pathogenetic theory for girls is formulated after surveying evidence including: (1) the thoracospinal concept for right thoracic AIS in girls; (2) the new neuroskeletal biology relating the sympathetic nervous system to bone formation/resorption and bone growth; (3) white adipose tissue storing triglycerides and the adiposity hormone leptin which functions as satiety hormone and sentinel of energy balance to the hypothalamus for long-term adiposity; and (4) central leptin resistance in obesity and possibly in healthy females. The new theory states that AIS in girls results from developmental disharmony expressed in spine and trunk between autonomic and somatic nervous systems. The autonomic component of this double neuro-osseous theory for AIS pathogenesis in girls involves selectively increased sensitivity of the hypothalamus to circulating leptin (genetically-determined up-regulation possibly involving inhibitory or sensitizing intracellular molecules, such as SOC3, PTP-1B and SH2B1 respectively), with asymmetry as an adverse response (hormesis); this asymmetry is routed bilaterally via the sympathetic nervous system to the growing axial skeleton where it may initiate the scoliosis deformity (leptin-hypothalamic-sympathetic nervous system concept = LHS concept). In some younger preoperative AIS girls, the hypothalamic up-regulation to circulating leptin also involves the somatotropic (growth hormone/IGF) axis which exaggerates the sympathetically-induced asymmetric skeletal effects and contributes to curve progression, a concept with therapeutic implications. In the somatic nervous system, dysfunction of a postural mechanism involving the CNS body schema fails to control, or may induce, the spinal deformity of AIS in girls (escalator concept). Biomechanical factors affecting ribs and/or vertebrae and spinal cord during growth may localize AIS to the thoracic spine and contribute to sagittal spinal shape alterations. The developmental disharmony in spine and trunk is compounded by any osteopenia, biomechanical spinal growth modulation, disc degeneration and platelet calmodulin dysfunction. Methods for testing the theory are outlined. Implications are discussed for neuroendocrine dysfunctions, osteopontin, sympathoactivation, medical therapy, Rett and Prader-Willi syndromes, infantile idiopathic scoliosis, and human evolution. AIS pathogenesis in girls is predicated on two putative normal mechanisms involved in trunk growth, each acquired in evolution and unique to humans.

Update on the management of idiopathic scoliosis

PURPOSE OF REVIEW

Idiopathic scoliosis is a lateral curvature of the spine greater than 10 degrees for which there is no known cause. This paper reviews the current literature on the appropriate evaluation and treatment of patients with idiopathic scoliosis.

RECENT FINDINGS

Improved technology and surgical techniques are allowing improved curve correction and improved quality of life for these patients. Specifically, the pedicle screw construct can provide excellent curve correction and stabilization for spinal deformities.

SUMMARY

Idiopathic scoliosis is a diagnosis of exclusion and the approach to a patient with scoliosis should aim toward ruling out other possible causes. In those patients with scoliosis necessitating treatment, bracing should be the first line of treatment and these patients should be followed up closely to track curve progression. Patients who fail conservative management may undergo spinal fusion with pedicle screw instrumentation. Vigilant monitoring and thorough evaluation of scoliosis patients can steer patients toward appropriate management in a judicious manner preventing the significant medical morbidity and deformity that scoliosis can insidiously inflict.

The pathogenesis of adolescent idiopathic scoliosis: review of the literature

STUDY DESIGN

Review of the literature on the pathogenesis of adolescent idiopathic scoliosis (AIS).

OBJECTIVE

To discuss the different theories that have appeared on this subject.

SUMMARY OF BACKGROUND DATA

The pathogenesis of AIS, a condition exclusive to humans, has been the subject of many studies. Over the years, practically every structure of the body has been mentioned in the pathogenesis of AIS; however, the cause of this spinal deformity remains little understood. The pathogenesis of this condition is termed multifactorial.

METHODS

PubMed and Google Scholar electronic databases were searched focused on parameters concerning the pathogenesis of adolescent idiopathic scoliosis. The search was limited to the English language.

RESULTS

No single causative factor for the development of idiopathic scoliosis has been identified, it is thus termed multifactorial. AIS is a complex genetic disorder. The fully erect posture, which is unique to humans, seems to be a prerequisite for the development of AIS.

CONCLUSION

Although any or all of the mentioned factors in this review may play a certain role in the initiation and progression of AIS at a certain stage, the presented material suggests that in the observed deformation, genetics, and the unique mechanics of the fully upright human spine play a decisive role.