Is decreased bone mineral density associated with development of scoliosis? A bipedal osteopenic rat model

The Relationship Between Scoliosis, Spinal Bone Density, and Truncal Muscle Strength in Familial Dysautonomia Patients

This combined retrospective and prospective study aimed to investigate the relationship between scoliosis, spinal bone mineral density (BMD), and truncal muscle strength in patients with familial dysautonomia (FD). A total of 79 FD patients (40 male, 39 female) aged 5-44 years were included. The severity of scoliosis, lumbar spine BMD (Z-score), and truncal muscle strength were assessed. Correlations were analyzed using Pearson's correlation coefficient. Inverse correlations were observed between scoliosis severity and BMD (r = - 0.328, p = 0.001), as indicated by increasingly negative Z-score values with worsening osteoporosis. There were also inverse correlations between scoliosis and truncal muscle strength (r = - 0.595, p < 0.001). The correlation between scoliosis and age was notable up to 22 years (r = 0.421, p = 0.01), but not in the older age group (22-44 years). Our study identified inverse correlations between osteoporosis and scoliosis, as well as between scoliosis and truncal muscle strength, in FD patients. These findings suggest that there may be a relationship between bone density, muscle strength, and the severity of spinal curvature in this population. While our results highlight the potential importance of early diagnosis and management of osteoporosis, and possibly the benefits of physical therapy to strengthen truncal muscles, further research is needed to determine the direct impact of these interventions on preventing the progression of scoliosis and its associated complications in FD patients. A long-term longitudinal study could provide more insights into these relationships and inform treatment strategies for FD patients.

Differential Gene Expression Profiles and Pathways Highlight the Role of Osteoimmunology in Neurofibromatosis Type 1-Related Dystrophic Scoliosis With Osteopenia

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 human trabecular bone (HTB)-derived cells of dystrophic scoliosis secondary to neurofibromatosis type 1 (DS-NF1) and compare these to normal controls.

SUMMARY OF BACKGROUND DATA

The pathogenesis of DS-NF1 and the accompanying generalized osteopenia remain unclear. We hypothesized that HTBs may play a significant role in the etiology and pathogenesis of DS-NF1.

MATERIALS AND METHODS

Microarray analysis was used to identify differentially expressed genes of HTBs from patients with DS-NF1 compared with those from healthy individuals. Functional and pathway enrichment analysis were implemented through Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway database. Then, the "search tool for the retrieval of interacting genes/proteins" database, Cytoscape, and "Molecular Complex Detection" were applied to construct the protein-protein interaction (PPI) network and screen hub genes. Pathway enrichment analysis was further performed for hub genes and gene clusters identified through module analysis. Six potential crucial genes were selected for validation by reverse transcription polymerase chain reaction.

RESULTS

Bioinformatic analysis revealed that there are 401 previously unrecognized differentially expressed genes (238 up and 163 downregulated genes) in HTBs from patients with DS-NF1, and they were mainly enriched in terms of immune response, type-I interferon (IFN) signaling, TNF signaling pathway and etinoic acid inducible gene I-like receptor signaling pathway. Five hub genes, including signal transducer and activator of transcription 1, 2'-5'-oligoadenylate synthetase-like, IFN induced with helicase C domain 1, IFN regulatory factor 7, and MX dynamin-like GTPase 1 were identified through PPI network, which were mainly enriched in terms of Jak-STAT and etinoic acid inducible gene I-like receptor signaling pathway. An independently dysregulated protein cluster containing CCL2, CXCL1, CXCL3, CX3CL1, TLR1 , and CXCL12 was also identified through the PPI network. This indicated that the upper abnormally expressed genes may play essential roles in DS-NF1 pathogenesis and accompanied osteopenia.

CONCLUSION

Six key genes were identified in the progression of DS-NF1-related osteopenia. Immune response might play a key role in the progression of osteopenia, whereas a CXCL12 -mediated osteogenic effect might play a protective role.

Estrogen promotes the onset and development of idiopathic scoliosis via disproportionate endochondral ossification of the anterior and posterior column in a bipedal rat model

This study aimed to verify the effects of estrogen on the onset and development of adolescent idiopathic scoliosis and the mechanisms associated with these effects by constructing a pubescent bipedal rat model. Experiments were conducted to investigate whether scoliosis progression was prevented by a Triptorelin treatment. One hundred twenty bipedal rats were divided into female, OVX (ovariectomy), OVX + E2, Triptorelin, sham, and male groups. According to a spinal radiographic analysis, the scoliosis rates and curve severity of the female and OVX + E2 groups were higher than those in the OVX, Triptorelin, and male groups. The measurements obtained from the sagittal plane of thoracic vertebrae CT confirmed a relatively slower growth of the anterior elements and a faster growth of the posterior elements between T11 and T13 in the female and OVX + E2 groups than in the OVX and Triptorelin groups. Histomorphometry and immunohistochemistry revealed a significantly longer hypertrophic zone of the vertebral cartilage growth plates that expressed more type X collagen and less type II collagen in the OVX and Triptorelin groups than in the female and OVX + E2 groups. Ki67 immunostaining confirmed an increase in the proliferation of vertebral growth plate chondrocytes in the OVX group compared with the female and OVX + E2 groups. In conclusion, estrogen obviously increased the incidence of scoliosis and curve severity in pubescent bipedal rats. The underlying mechanism may be a loss of coupling of the endochondral ossification between the anterior and posterior columns. Triptorelin decreased the incidence of scoliosis and curve magnitudes in bipedal female rats.

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.

Key role for the transcriptional factor, osterix, in spine development

BACKGROUND CONTEXT

Osterix (Osx) is an important transcriptional factor for bone formation; however, its role in spine development has not been determined.

PURPOSE

The goal of the present study is to observe the role of Osx in spine development.

STUDY DESIGN/SETTING

Deletion and overexpression of Osx were achieved in Osx knockout and transgenic mice, respectively, to determine the effect of Osx on spine development.

METHODS

With 2.3-kb type I collagen as a promoter, Osx were deleted in mice, and overexpression of Osx was obtained in Osx transgenic mice. Video, X-ray radiology, histology, tartrate-resistant acid phosphatase staining, Safranin O staining, and immunohistochemistry were used to assess the effect of Osx deletion and overexpression on spine development. This study was supported by National Science Foundation of China (81271935) and Foundation of State Key Laboratory of Trauma, Burns and combined injury (SKLZZ SKLZZ201124). No potential conflict of interest to disclose.

RESULTS

Overexpression of Osx did not have an obvious effect on spine development, whereas deletion of Osx led to severe spine deformities that included wedged vertebrae, spinal stenosis, and congenital scoliosis. Also, Osx deactivation resulted in shortened vertebrae and excessive bone volume in the vertebrae. TRAP staining showed that activity of osteoclasts decreased in Osx-null mice, and examination with TdT-mediated dUTP nick end labeling revealed that the apoptosis rate at the growth plate decreased significantly in Osx-null mice. Excessive formation of bone was positive for Safranin O staining.

CONCLUSIONS

Osx plays an important role in spine development, and its deactivation leads to severe spine deformities.

Comparison of the sagittal profiles among thoracic idiopathic scoliosis patients with different Cobb angles and growth potentials

Background

Previous studies have demonstrated that pelvic incidence and sacral slope are significantly greater in idiopathic scoliosis patients compared with normal adolescents. However, whether these sagittal parameters are related to the progression of scoliosis remain unknown. The present was designed to determine the differences in the sagittal profiles among thoracic idiopathic scoliosis patients with different potentials for curve progression.

Methods

Ninety-seven outpatient idiopathic scoliosis patients enrolled from June 2008 to June 2011 were divided to three groups according to different Cobb angles and growth potentials: (1) non-progression of thoracic curve group, Risser sign of 5 and Cobb’s angle < 40°; (2) moderate progression of thoracic curve group, Risser sign of 5 and Cobb’s angle ≥ 40°; and (3) severe progression of thoracic curve group, Risser sign ≤ 3 and Cobb’s angle ≥ 40°. All patients underwent whole spinal anteroposterior and lateral X-ray in standing position, and the sagittal parameters were measured, including thoracic kyphosis, lumbar lordosis, sacral slope, pelvic incidence, and pelvic tilt.

Results

The average thoracic scoliosis Cobb’s angle in the non-progression group was significantly less than that in the moderate progression group (P < 0.01) and severe progression group (P < 0.01), but there was no statistical difference in the average thoracic scoliosis Cobb’s angle between the severe progression group and moderate progression group. The average thoracic kyphosis angle in the severe progression group (9° ± 4°) was significantly smaller than that in the non-progression group (18° ± 6°, P < 0.01) and moderate progression group (14° ± 5°, P < 0.05). No statistical differences were present in the average lumbar lordosis, sacral slope, pelvic incidence, and pelvic tilt among the three groups.

Conclusions

Thoracic hypokyphosis is strongly related with the curve progression in thoracic idiopathic scoliosis patients, but not pelvic sagittal profiles.

Identification of the relationships between sagittal plane and coronal plane curvature in guppy models

OBJECTIVE

To explore the relationship between sagittal plane and coronal plane curvatures in guppies by investigating the curvature angles of sagittal and sagittal-coronal guppies.

METHODS

After mating between 1000 spinal curvature guppies, 124 guppies (3-month old) were screened from progenies for the present study. Photos of all fishes were taken and the sagittal and coronal angles were calculated via angle measure tool of Photoshop 12.0 software. All data were analyzed by SPSS 11.0.

RESULTS

In sagittal and sagittal-coronal curvature guppies, there was a significant linear correlation between sagittal angles and coronal angles. In 48 sagittal-coronal curvatures, their sagittal angles were above 40°, meanwhile, in 76 sagittal guppies, their sagittal angles were mostly below 40°.

CONCLUSIONS

These findings indicated that the occurrence of coronal curvature might be later than sagittal curvature and could be influenced by other factors. Sagittal angles 40° might be involved in the onset of coronal curvature.

Selective estrogen receptor modulation prevents scoliotic curve progression: radiologic and histomorphometric study on a bipedal C57Bl6 mice model

PURPOSE

Previous work has suggested that progression of experimental scoliotic curves in pinealectomized chicken and bipedal C57BL6 mice models may be prevented and reversed with Tamoxifen treatment. Raloxifene is another Selective Estrogen Receptor Modulator (SERM) with estrogen agonist effects on bone and increases bone density but with fewer side effects on humans. To investigate whether scoliosis progression in bipedal C57Bl6 mice model could be prevented with SERM treatment and the mechanisms associated with this effect.

METHODS

Eighty C57BL6 mice were rendered bipedal and divided into Tamoxifen (TMX), Raloxifene (RLX) and control groups. TMX and RLX groups received orally administered TMX and RLX for 40 weeks. Anteroposterior X-ray imaging and histomorphometric analysis (at 20th and 40th weeks) were performed.

RESULTS

At 20th week, TMX and RLX groups displayed higher rates (p = 0.033, p = 0.029) and larger curve magnitudes (p = 0.018). At 40th week, curve rates were similar between the groups but the curve magnitudes in TMX and RLX groups were smaller (p = 0.001). Histomorphometry revealed that treated animals had higher trabecular density (p = 0.04), lower total intervertebral disc (p = 0.038) and growth plate volumes (p = 0.005) and smaller vertebral bodies (p = 0.016).

CONCLUSIONS

Treatment with TMX or RLX did not reduce the incidence of scoliosis but decreased the curve magnitudes at 40 weeks. The underlying mechanism associated with the decrease in curve magnitudes may be the early maturation of growth plates, thereby possible deceleration of the growth rate of the vertebral column and increase in bone density. RLX is as effective as TMX in preventing the progression of scoliotic curves in melatonin deficient bipedal mice.

Adolescent idiopathic scoliosis and eating disorders: is there a relation? Results of a cross-sectional study

A recent study suggests a correlation between idiopathic scoliosis in adolescence and eating disorders. However, this does not correspond with our clinical experience in the same population. The aim of this study was to verify the correlation between scoliosis and eating disorders in adolescence. A cross-sectional study was designed including 187 consecutive adolescent girls with a diagnosis of idiopathic scoliosis (mean Cobb angle 26°, range 11-73°, age 15.2±2.5; 24% juveniles, 76% adolescent type) and 93 schoolgirls as controls (age 14.9±1.0). All of the participants answered the Italian validated questionnaire EAT-26 about eating habits in order to identify any eating disorders. Body mass index (BMI) was calculated for all participants and compared to reference data.

STATISTICAL ANALYSIS

chi-square test, Student's t-test, Pearson's correlation coefficient. Only 3 (1.6%; 95% CI -0.2-3.4%) participants in the scoliosis group showed EAT-26 scores suggestive for eating disorders versus 7 (7.5%; 95% CI 2.2-12.9%) in the school population (p<0.05). The BMI was slightly lower (p<0.05) for scoliosis patients (19±0.2) than for school girls (21±0.3). EAT-26 is recognized among the most valid questionnaires for eating disorders and has been widely applied in various countries. By applying this questionnaire, a lower incidence of eating disorders in female scoliosis patients was found than in the general population (using both our own controls and Italian reference values). This contrasts with some expert opinions and a recent study performed in Italy. The low BMI already reported in the literature as being typical of scoliosis participants is confirmed by our data.

Idiopathic scoliosis: etiological concepts and hypotheses

Scoliosis is diagnosed as idiopathic in 70 % of structural deformities affecting the spine in children and adolescents, probably reflecting our current misunderstanding of this disease. By definition, a structural scoliosis should be the result of some primary disorder. The goal of this article is to give a comprehensive overview of the currently proposed etiological concepts in idiopathic scoliosis regarding genetics, molecular biology, biomechanics, and neurology, with particular emphasis on adolescent idiopathic scoliosis (AIS). Despite the fact that numerous potential etiologies for idiopathic scoliosis have been formulated, the primary etiology of AIS remains unknown. Beyond etiology, identification of prognostic factors of AIS progression would probably be more relevant in our daily practice, with the hope of reducing repetitive exposure to radiation, unnecessary brace treatments, psychological implications, and costs-of-care related to follow-up in low-risk patients.

The metabolic basis of adolescent idiopathic scoliosis: 2011 report of the "metabolic" workgroup of the Fondation Yves Cotrel

OBJECTIVE

The purpose of this review is to elucidate the metabolic processes involved in the pathogenesis of adolescent idiopathic scoliosis (AIS) in light of research by the present authors as well as current literature.

METHODS

Pathogenetic mechanisms involved in AIS were modeled as (a) a form of neuromuscular scoliosis (in conjunction with an adverse mechanical environment such as bipedality), in which hormonal and other chemical factors act as regulators of skeletal muscle tone and function; (b) as a consequence of an abnormality in growth of the spinal column (in conjunction with an adverse mechanical environment such as bipedality), in which hormones and other chemical factors act as regulators of growth; and (c) as a mechanical failure of one side of the vertebral column due to a defect in trabecular formation or mineralization (in conjunction with an adverse mechanical environment such as bipedality); in which hormonal and other chemical factors act as regulators of bone formation, mineralization and/or resorption.

RESULTS AND CONCLUSION

Current evidence supporting these models individually or in combination is discussed.