Association between the development of the body axis and the craniofacial skeleton studied by immunohistochemical analyses using collagen II, Pax9, Pax1, and Noggin antibodies

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Transcriptional analysis of cleft palate in TGFβ3 mutant mice

Cleft palate (CP) is one of the most common craniofacial birth defects, impacting about 1 in 800 births in the USA. Tgf-β3 plays a critical role in regulating murine palate development, and Tgf-β3 null mutants develop cleft palate with 100% penetrance. In this study, we compared global palatal transcriptomes of wild type (WT) and Tgf-β3 −/− homozygous (HM) mouse embryos at the crucial palatogenesis stages of E14.5, and E16.5, using RNA-seq data. We found 1,809 and 2,127 differentially expressed genes at E16.5 vs. E14.5 in the WT and HM groups, respectively (adjusted p < 0.05; |fold change|> 2.0). We focused on the genes that were uniquely up/downregulated in WT or HM at E16.5 vs. E14.5 to identify genes associated with CP. Systems biology analysis relating to cell behaviors and function of WT and HM specific genes identified functional non-Smad pathways and preference of apoptosis to epithelial-mesenchymal transition. We identified 24 HM specific and 11 WT specific genes that are CP-related and/or involved in Tgf-β3 signaling. We validated the expression of 29 of the 35 genes using qRT-PCR and the trend of mRNA expression is similar to that of RNA-seq data . Our results enrich our understanding of genes associated with CP that are directly or indirectly regulated via TGF-β.

Cone beam computed tomography evaluation of the relationship between atlantodental interval and skeletal facial morphology in adolescents

Introduction

In the pediatric population, computed tomography examination of the upper cervical spine plays an important role in the diagnosis of neurological injuries involving that region. Due to the interconnected nature of the craniofacial structures, a structural change in one is expected to also cause changes in the other structures.

Objective

The aim of this study was to evaluate relationships between atlantodental interval, cervical vertebral morphology, and facial structure in healthy adolescents using cone beam computed tomography.

Methods

Thirty subjects aged 14–20 years (10 males, mean age: 17.2 years; 20 females, mean age: 17.9 years) were included in the study. The anterior, lateral and posterior atlantodental intervals, and vertical and anteroposterior dimensions of the first and second cervical vertebrae were evaluated from cone beam computed tomography images. Facial morphology was evaluated using 7 parameters on lateral cephalometric cone beam computed tomography images and 6 parameters on posteroanterior images. The Mann–Whitney U test and Wilcoxon test were used for statistical analyses.

Results

Comparisons between males and females showed that most parameters were larger in males, with significant differences in vertical facial dimensions (anterior lower face height: p = 0.05; anterior upper face height: p = 0.001), (distance between the most internal point of the frontozygomatic suture and midsagittal reference plane; p = 0.01), (the distance between the deepest point of the right alveolar maxillar process and midsagittal reference plane; p = 0.001), and C2 vertebral dimensions. The anterior and lateral atlantodental interval values correlated with maxilla position relative to the mandible angle, and the anterior atlantodental interval correlated with lower anterior facial height (p = 0.05). Dimensional measurements of the C1 and C2 vertebrae were correlated with both anterior facial heights and some posteroanterior parameters.

Conclusion

Sagittal, vertical, and transverse facial dimensions and positions were strongly associated with C1 and C2 vertebral dimensions, and the maxillomandibular relationship may affect atlantodental interval. Therefore, including craniofacial features in assessment of the atlantodental area and vertebral distances in adolescents may be beneficial.

Unusual osteological findings in sacred relics from the LESJE monastery in central Serbia

An adult male skeleton was submitted to the Department of Anatomy at the University of Belgrade for evaluation. It was believed to represent the remains of a second to third century Christian saint from the Lesje Monastery in central Serbia. Examination of the remains revealed an old crush fracture of a thoracic vertebra and an unusual, probably congenital, malformation of the atlanto-occipital joint with deformation of the left occipital condyle and resultant narrowing of the foramen magnum. Although the occipital malformations were most likely congenital, they may still have caused, or contributed to, death by compression of the underlying upper cervical spinal cord.

Generation of Pax1/PAX1-Specific Monoclonal Antibodies

Pax genes encode an evolutionary conserved group of transcription factors with multiple roles during embryonic development and for cell type specification in normal and malignant tissues of the adult organism. In mice, Pax1 is required for the formation of specific skeletal structures as well as for the development of a fully functional thymus. In humans, the PAX1 locus has been linked to otofaciocervical syndrome, idiopathic scoliosis, and to a higher susceptibility for androgenic alopecia. In addition, the methylation status of PAX1 has recently emerged as a sensitive marker for predictive screening of cervical cancer. To provide a reagent for reproducible detection of Pax1 expression, we have generated rat monoclonal antibodies (MAbs) against the murine Pax1 protein. MAbs of one clone (clone 5A2) specifically detect mouse Pax1 protein in Western blot analyses. Moreover, the anti-Pax1 MAbs cross-react with human PAX1 protein and are applicable in immunohistochemical detection procedures using paraformaldehyde/formalin-fixed tissues embedded in paraffin. The anti-Pax1 MAbs provide a reliable reagent for reproducible Pax1/PAX1 protein expression analyses and, therefore, may help to improve diagnostic protocols in clinical settings involving deregulated expression of Pax1/PAX1.

Tooth agenesis and craniofacial morphology in pre-orthodontic children with and without morphological deviations in the upper cervical spine

AIM: To analyze differences in prevalence and pattern of tooth agenesis and craniofacial morphology between non syndromic children with tooth agenesis with and without upper cervical spine morphological deviations and to analyze associations between craniofacial morphology and tooth agenesis in the two groups together.

METHODS: One hundred and twenty-six pre-orthodontic children with tooth agenesis were divided into two groups with (19 children, mean age 11.9) and without (107 children, mean age 11.4) upper spine morphological deviations. Visual assessment of upper spine morphology and measurements of craniofacial morphology were performed on lateral cephalograms. Tooth agenesis was evaluated from orthopantomograms.

RESULTS: No significant differences in tooth agenesis and craniofacial morphology were found between children with and without upper spine morphological deviations (2.2 ± 1.6 vs 1.94 ± 1.2, P > 0.05) but a tendency to a different tooth agenesis pattern were seen in children with morphological deviations in the upper spine. In the total group tooth agenesis was associated with the cranial base angle (n-s-ba, r = 0.23, P < 0.01), jaw angle (ML/RLar, r = 0.19, P < 0.05), mandibular inclination (NSL/ML, r = -0.21, P < 0.05), mandibular prognathia (s-n-pg, r = 0.25, P < 0.01), sagittal jaw relationship (ss-n-pg, r = -0.23, P < 0.5), overjet (r = -0.23, P < 0.05) and overbite (r = -0.25, P < 0.01).

CONCLUSION: Etiology of tooth agenesis in children with upper spine morphological deviations was discussed. The results may be valuable for the early diagnosis and treatment planning of non syndromic children with tooth agenesis.

Quantitative trait loci affecting the 3D skull shape and size in mouse and prioritization of candidate genes in-silico

We describe the first application of high-resolution 3D micro-computed tomography, together with 3D landmarks and geometric morphometrics, to map QTL responsible for variation in skull shape and size using a backcross between C57BL/6J and A/J inbred strains. Using 433 animals, 53 3D landmarks, and 882 SNPs from autosomes, we identified seven QTL responsible for the skull size (SCS.qtl) and 30 QTL responsible for the skull shape (SSH.qtl). Size, sex, and direction-of-cross were all significant factors and included in the analysis as covariates. All autosomes harbored at least one SSH.qtl, sometimes up to three. Effect sizes of SSH.qtl appeared to be small, rarely exceeding 1% of the overall shape variation. However, they account for significant amount of variation in some specific directions of the shape space. Many QTL have stronger effect on the neurocranium than expected from a random vector that will parcellate uniformly across the four cranial regions. On the contrary, most of QTL have an effect on the palate weaker than expected. Combined interval length of 30 SSH.qtl was about 315 MB and contained 2476 known protein coding genes. We used a bioinformatics approach to filter these candidate genes and identified 16 high-priority candidates that are likely to play a role in the craniofacial development and disorders. Thus, coupling the QTL mapping approach in model organisms with candidate gene enrichment approaches appears to be a feasible way to identify high-priority candidates genes related to the structure or tissue of interest.

The formation of endoderm-derived taste sensory organs requires a Pax9-dependent expansion of embryonic taste bud progenitor cells

In mammals, taste buds develop in different regions of the oral cavity. Small epithelial protrusions form fungiform papillae on the ectoderm-derived dorsum of the tongue and contain one or few taste buds, while taste buds in the soft palate develop without distinct papilla structures. In contrast, the endoderm-derived circumvallate and foliate papillae located at the back of the tongue contain a large number of taste buds. These taste buds cluster in deep epithelial trenches, which are generated by intercalating a period of epithelial growth between initial placode formation and conversion of epithelial cells into sensory cells. How epithelial trench formation is genetically regulated during development is largely unknown. Here we show that Pax9 acts upstream of Pax1 and Sox9 in the expanding taste progenitor field of the mouse circumvallate papilla. While a reduced number of taste buds develop in a growth-retarded circumvallate papilla of Pax1 mutant mice, its development arrests completely in Pax9-deficient mice. In addition, the Pax9 mutant circumvallate papilla trenches lack expression of K8 and Prox1 in the taste bud progenitor cells, and gradually differentiate into an epidermal-like epithelium. We also demonstrate that taste placodes of the soft palate develop through a Pax9-dependent induction. Unexpectedly, Pax9 is dispensable for patterning, morphogenesis and maintenance of taste buds that develop in ectoderm-derived fungiform papillae. Collectively, our data reveal an endoderm-specific developmental program for the formation of taste buds and their associated papilla structures. In this pathway, Pax9 is essential to generate a pool of taste bud progenitors and to maintain their competence towards prosensory cell fate induction.

Cervical vertebral column morphology and head posture in preorthodontic patients with anterior open bite

INTRODUCTION

Cervical vertebral column morphology and head posture were examined and related to craniofacial morphology in preorthodontic children and adolescents with anterior open bite.

METHODS

One hundred eleven patients (ages, 6-18 years) with an anterior open bite of more than 0 mm were divided into 2 groups of skeletal or dentoalveolar open bite. The skeletal open-bite group comprised 38 subjects (19 girls, 19 boys). The dentoalveolar open-bite group comprised 73 subjects (43 girls, 30 boys). Visual assessment of the cervical column and measurements of craniofacial morphology and head posture were made on profile radiographs.

RESULTS

Deviations in the cervical vertebral column morphology occurred in 23.7% of the subjects in the skeletal open-bite group and in 19.2% in the dentoalveolar open-bite group, but the difference was not significant. Head posture was significantly more extended in the skeletal open-bite group compared with the dentoalveolar open-bite group (craniovertical angle [Mx/VER], P <0.05; craniocervical angles [Mx/OPT, Mx/CVT], P <0.01. Only head posture was associated with craniofacial morphology: extended posture was associated with a large cranial base angle (P <0.01, P <0.001), large vertical craniofacial dimensions (P <0.05; P <0.01; P <0.001), and retrognathia of the jaws (P <0.001).

CONCLUSIONS

Cervical column morphology is described for the first time in children and adolescents with open bite. No significant differences in the cervical vertebral column's morphologic deviations were found between the skeletal and the dentoalveolar open-bite groups. Significant differences were found in head posture between the groups and with regard to associations with craniofacial dimensions. This might indicate a respiratory etiologic component in children with anterior open bite.

Associations between the Cervical Vertebral Column and Craniofacial Morphology

Aim. To summarize recent studies on morphological deviations of the cervical vertebral column and associations with craniofacial morphology and head posture in nonsyndromic patients and in patients with obstructive sleep apnoea (OSA). Design. In these recent studies, visual assessment of the cervical vertebral column and cephalometric analysis of the craniofacial skeleton were performed on profile radiographs of subjects with neutral occlusion, patients with severe skeletal malocclusions and patients with OSA. Material from human triploid foetuses and mouse embryos was analysed histologically. Results. Recent studies have documented associations between fusion of the cervical vertebral column and craniofacial morphology, including head posture in patients with severe skeletal malocclusions. Histological studies on prenatal material supported these findings. Conclusion. It is suggested that fusion of the cervical vertebral column is associated with development and function of the craniofacial morphology. This finding is expected to have importance for diagnostics and elucidation of aetiology and thereby for optimal treatment.

Associations between craniofacial morphology, head posture, and cervical vertebral body fusions in men with sleep apnea

INTRODUCTION

The aim of this study was to analyze craniofacial profiles and head posture in patients with obstructive sleep apnea (OSA) subgrouped according to cervical column morphology.

METHODS

Seventy-four white men aged 27 to 65 years (mean, 49.0 years) diagnosed with OSA in sleep studies by using overnight polysomnography were included. Only patients with apnea-hypopnea index scores between 5.1 and 92.7 (mean, 36.4) were included. Lateral profile radiographs in standardized head posture were taken, and cephalometric analyses of sagittal and vertical jaw relationships were made. The patients were divided into 4 groups according to fusion in the cervical vertebrae: group I, no fusions (42 subjects); group II, fusion of cervical vertebrae 2 and 3 (15 subjects); group III, occipitalization (10 subjects); and group IV, block fusion (11 subjects). Mean differences of craniofacial dimensions between the groups were assessed by unpaired t tests.

RESULTS

No significant differences were seen between groups I and III. Between groups I and II, significant differences were seen in jaw relationship (P < 0.05). Between groups I and IV, anterior face height and mandibular length deviated significantly. No significant differences were seen in head posture.

CONCLUSIONS

OSA patients with block fusions in the cervical vertebrae and fusion of 2 vertebrae differed significantly in craniofacial profile from other OSA patients.

Cervical vertebrae, cranial base, and mandibular retrognathia in human triploid fetuses

On profile radiographs of adults, an association between fusions of cervical vertebrae, deviations in the cranial base and mandibular retrognathia has been documented radiographically. An elaboration of this association on a histological level is needed. In human triploid fetuses severe mandibular retrognathia and deviations in the cranial base have previously been described radiographically (without cephalometry) and cervical column fusions radiographically as well as histologically. Therefore, triploid fetuses were chosen to elucidate the cranial base cephalomterically and histologically. In the present study, eight triploid fetuses were analyzed radiographically and histologically focusing especially on the cranial base, which borders to the spine and to which the jaws are attached. A histological analysis of the cranial base has not previously been performed in triploid cases. An enlarged cranial base angle and a retrognathic position of the mandible were documented cephalometrically on radiographs of all cases. Histologically, malformations were observed in the cranial base as well as in the spine. These are new findings indicating the association between the occipital bone and the uppermost vertebra in the body axis. As the notochord connects the cervical column and the cranial base in early prenatal life, molecular signaling from the notochord may in future studies support the notochord as the developmental link between abnormal development in the spine and the cranial base.