Imaging and histologic features of traumatic temporomandibular joint ankylosis

Temporal gene expression profiling during early-stage traumatic temporomandibular joint bony ankylosis in a sheep model

BACKGROUND

Investigating the molecular biology underpinning the early-stage of traumatic temporomandibular joint (TMJ) ankylosis is crucial for discovering new ways to prevent the disease. This study aimed to explore the dynamic changes of transcriptome from the intra-articular hematoma or the newly generated ankylosed callus during the onset and early progression of TMJ ankylosis.

METHODS

Based on a well-established sheep model of TMJ bony ankylosis, the genome-wide microarray data were obtained from samples at postoperative Days 1, 4, 7, 9, 11, 14 and 28, with intra-articular hematoma at Day 1 serving as controls. Fold changes in gene expression values were measured, and genes were identified via clustering based on time series analysis and further categorised into three major temporal classes: increased, variable and decreased expression groups. The genes in these three temporal groups were further analysed to reveal pathways and establish their biological significance.

RESULTS

Osteoblastic and angiogenetic genes were found to be significantly expressed in the increased expression group. Genes linked to inflammation and osteoclasts were found in the decreased expression group. The various biological processes and pathways related to each temporal expression group were identified, and the increased expression group comprised genes exclusively involved in the following pathways: Hippo signaling pathway, Wnt signaling pathway and Rap 1 signaling pathway. The decreased expression group comprised genes exclusively involved in immune-related pathways and osteoclast differentiation. The variable expression group consisted of genes associated with DNA replication, DNA repair and DNA recombination. Significant biological pathways and transcription factors expressed at each time point postoperatively were also identified.

CONCLUSIONS

These data, for the first time, presented the temporal gene expression profiling and reveal the important process of molecular biology in the early-stage of traumatic TMJ bony ankylosis. The findings might contributed to identifying potential targets for the treatment of TMJ ankylosis.

Temporomandibular Joint Ankylosis in a Girl Child: Immunochemical Evaluation of Tissue Material Obtained from Repeated Arthroplasty Surgeries

Temporomandibular joint ankylosis (TMJA) is a rare, but debilitating, condition that leads to TMJ joint hypomobility. Surgery is the mainstay for treatment, which is accompanied by rehabilitative and psychological support. Despite the advances in surgical techniques, the recurrence of TMJA post-surgery has been reported as a common complication. Therefore, it becomes essential to investigate and understand the histo-morpho-pathological processes governing these ankylotic changes. Given the lack of such studies in the literature, herein we present a case of a girl child who underwent primary surgery at the age of six years, followed by a second surgery at the age of twelve years. Ankylotic tissue samples collected during both surgeries were studied using various immunohistochemical markers for tissue remodeling, inflammation, antimicrobial activity, and transcriptional regulation. The expression of MMP-2 and -9 was downregulated in repeated surgery materials, whilst MMP-13 was rarely detected in both tissues. Strong MMP-8, TIMP-2, and TIMP-4 expressions were noted in both tissues, showing their anti-inflammatory and protective roles. Moderately strong expression of bFGF, FGFR-1, IL-1α, and TNF-α could indicate sustained tissue growth in the background of inflammation (wound healing). Interestingly, the expression of β-defensin-2 was found to be constant in both tissues, thereby indicating possible ECM remodeling and collagen breakdown. Finally, a moderate expression of RUNX-2, coupled with a low expression of WNT-1 and -3a, could indicate a slow and delayed bone regeneration process. Our results showcase the complex myriad of pathways that could be involved in the progression of TMJA and post-surgery healing processes. Immunopathological studies could aid in improving the diagnosis, treatment, and prognosis for patients affected with TMJA.

Traumatic temporomandibular joint bony ankylosis in growing rats

BACKGROUND

The pathogenesis of traumatic temporomandibular joint (TMJ) bony ankylosis remains unknown. This study aimed to explore the pathogenesis of traumatic TMJ bony ankylosis in a rat model.

METHODS

Twenty-four 3-week-old male Sprague-Dawley rats were used in this study. Excision of the whole disc, the fibrocartilage damage of the condyle and glenoid fossa, and narrowed joint space were performed in the left TMJ of the operation group to induce TMJ bony ankylosis (experimental side). The right TMJ underwent a sham operation (sham side). The control group did not undergo any operations. At 1, 4, and 8 weeks postoperatively, rats of the operation group were sacrificed and TMJ complexes were evaluated by gross observation, Micro-CT, histological examinations, and immunofluorescence microscopy. Total RNA of TMJ complexes in the operation group were analyzed using RNA-seq.

RESULTS

Gross observations revealed TMJ bony ankylosis on the experimental side. Micro-CT analysis demonstrated that compared to the sham side, the experimental side showed a larger volume of growth, and a considerable calcified bone callus formation in the narrowed joint space and on the rougher articular surfaces. Histological examinations indicated that endochondral ossification was observed on the experimental side, but not on the sham side. RNA-seq analysis and immunofluorescence revealed that Matrix metallopeptidase 13 (MMP13) and Runt-related transcription factor 2 (RUNX2) genes of endochondral ossification were significantly more downregulated on the experimental side than on the sham side. The primary pathways related to endochondral ossification were Parathyroid hormone synthesis, secretion and action, Relaxin signaling pathway, and IL-17 signaling pathway.

CONCLUSIONS

The present study provided an innovative and reliable rat model of TMJ bony ankylosis by compound trauma and narrowed joint space. Furthermore, we demonstrated the downregulation of MMP13 and RUNX2 in the process of endochondral ossification in TMJ bony ankylosis.

Differences in the biological properties of mesenchymal stromal cells from traumatic temporomandibular joint fibrous and bony ankylosis: a comparative study

The aim of this study was to compare the functional characteristics of mesenchymal stromal cells (MSCs) from a sheep model of traumatic temporomandibular joint (TMJ) fibrous and bony ankylosis. A sheep model of bilateral TMJ trauma-induced fibrous ankylosis on one side and bony ankylosis on the contralateral side was used. MSCs from fibrous ankylosed callus (FA-MSCs) or bony ankylosed callus (BA-MSCs) at weeks 1, 2, 4, and 8 after surgery were isolated and cultured. MSCs derived from the bone marrow of the mandibular condyle (BM-MSCs) were used as controls. The MSCs from the different sources were characterized morphologically, phenotypically, and functionally. Adherence and trilineage differentiation potential were presented in the ovine MSCs. These cell populations highly positively expressed MSC-associated specific markers, namely CD29, CD44, and CD166, but lacked CD31 and CD45 expressions. The BA-MSCs had higher clonogenic and proliferative potentials than the FA-MSCs. The BA-MSCs also showed higher osteogenic and chondrogenic potentials, but lower adipogenic capacity than the FA-MSCs. In addition, the BA-MSCs demonstrated higher chondrogenic, but lower osteogenic capacity than the BM-MSCs. Our study suggests that inhibition of the osteogenic and chondrogenic differentiations of MSCs might be a promising strategy for preventing bony ankylosis in the future.

Microarray Analysis of Differential Gene Expression Between Traumatic Temporomandibular Joint Fibrous and Bony Ankylosis in a Sheep Model

Background

The type of traumatic temporomandibular joint (TMJ) ankylosis depends on the degree of severity of TMJ trauma. Here, we performed comprehensive differential molecular profiling between TMJ fibrous and bony ankylosis.

Material/Methods

Six sheep were used and a bilateral different degree of TMJ trauma was performed to induce fibrous ankylosis in one side and bony ankylosis in the other side. The ankylosed calluses were harvested at days 14 and 28 postoperatively and analyzed by Affymetrix OviGene-1_0-ST microarrays. DAVID was used to perform the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis for the different expression genes (DEGs). The DEGs were also typed into protein–protein interaction (PPI) networks to get the interaction data. Ten DEGs, including 7 hub genes from PPI analysis, were confirmed by real-time PCR.

Results

We found 90 and 323 DEGs at least 2-fold at days 14 and 28, respectively. At day 14, bony ankylosis showed upregulated DEGs, such as TLR8, SYK, NFKBIA, PTPRC, CD86, ITGAM, and ITGAL, indicating a stronger immune and inflammatory response and cell adhesion, while genes associated with anti-adhesion (PRG4) and inhibition of osteoblast differentiation (SFRP1) had higher expression in fibrous ankylosis. At day 28, bony ankylosis showed increased biological process related to new bone formation, while fibrous ankylosis was characterized by a prolonged immune and inflammatory reaction.

Conclusions

This study provides a differential gene expression profile between TMJ fibrous and bony ankylosis. Further study of these key genes may provide new ideas for future treatment of TMJ bony ankylosis.

Dysregulated healing response participates in the pathophysiology of temporomandibular joint ankylosis

This study aimed to characterize samples from patients diagnosed with TMJ ankylosis, using both clinical and histological data. Both clinical and histological analyses of retrieved tissue samples from patients with primary TMJ ankyloses were performed retrospectively (1980-2012). All patients had been subjected to primary arthroplasty. Our study analyzed connective tissue differentiation, ossification patterns, and bone resorption, using histology and immunohistochemistry. Fifteen case records, with a sex ratio of 4:1 (men:woman) and a median age of 8 years, were collected. Six patient samples reported a previous inflammatory event. Histologically, 15 samples exhibited fibrous tissue. Among these, 13 displayed bone at different stages of maturity (fibrous/bony ankylosis). Eleven samples showed aberrant cartilage, characterized by hypertrophic chondrocyte-like cells at the bone/cartilage interface. Four samples revealed inflammatory infiltrate; in one case, this was organized as a lymphoid follicle. Eleven samples showed bone resorption by attached osteoclasts. Interestingly, non-attached osteoclasts were detected, suggesting locally impaired bone remodeling. An association between the presence of mature/lamellar bone and the presence of osteoclasts was observed (p = 0.03). No association was found between previous history of either trauma or infection and the histological type of ankylosis (p = 0.74). There was no association between the histological presence of inflammation or infection and the type of ankylosis (p = 0.63 and p = 0.87, respectively). Retrieved TMJ ankylosis tissues displayed both aberrant ossification and reduced focal bone resorption, suggesting a dysregulated healing response.

Pathogenesis of traumatic temporomandibular joint ankylosis: a narrative review

OBJECTIVE

To comprehensively review the literature and summarize the results from human and animal studies related to the possible causes and pathogenesis of traumatic temporomandibular joint ankylosis (TMJA).

MATERIALS AND METHODS

The Google Scholar, Embase, and Web of Science databases were used to search for articles related to traumatic TMJA from 2011 to 2020. All articles were screened according to the inclusion and exclusion criteria, collected, and analyzed.

RESULTS

Nineteen relevant articles were collected. These articles were classified into three groups: predisposing and etiological factors, cellular studies, and molecular studies.

CONCLUSION

The pathological mechanisms are similar between TMJA and nonunion hypertrophy. Aberrant structural and etiological factors as well as disordered cellular and molecular mechanisms might contribute to TMJA formation. Although preclinical and clinical data have provided new evidence on the pathogenesis of traumatic TMJA, the molecular mechanisms and biological events require further exploration.

Efficacy of temporomandibular joint arthroplasty and insertion of a Matthews device as treatment for ankylosis of the joint: a case series

Temporomandibular joint (TMJ) ankylosis is a condition in which bony or fibrous adhesion of the anatomical joint components results in loss of function. This is particularly distressing and debilitating for patients who struggle to maintain good oral hygiene, which results in additional pain, oral disease, and ultimately, a poor aesthetic profile. A retrospective chart review was carried out to document the cases of three patients who attended a single centre for the management of ankylosis of the TMJ. Consent for chart review and use of photographs was gained from each one. Charts were obtained, records reviewed, and each of the cases written up for presentation in a case series. All three underwent arthroplasty of the TMJ and insertion of Matthews devices (two patients unilateral, one bilateral). All were followed up postoperatively. They experienced significant improvements in vertical mouth opening which have been maintained to the present. The Matthews device allows movement and physiotherapy postoperatively whilst maintaining the surgically created space. This prevents impingement on the tissues placed between the glenoid fossa and mandible, and appears to prevent relapse and further ankylosis. To our knowledge, few studies to date have documented the use of the Matthews device following interpositional arthroplasty of the TMJ.

A new clinical classification and treatment strategies for temporomandibular joint ankylosis

Temporomandibular joint ankylosis (TMJA) is a complicated condition that affects not only the condyle, but also the maxillofacial complex. Thus, it is often challenging to find a standardized treatment strategy for TMJA. This study was performed to analyse our experience with 95 TMJA patients over a 4-year period and develop a new classification system ('CDA'). The CDA classification system divides TMJA patients into eight different groups according to the preservability of the condyle (C), severity of the dentofacial bone deformity (D), and skeletal age (A). The 95 patients (129 ankylosed joints) were treated using different strategies based on this CDA classification. Treatment options included preserving or reconstructing the condylar head, surgical correction of jaw deformities, and close follow-up of mandibular growth. After treatment, all 129 ankylosed joints were completely released and the average maximum inter-incisal opening (MIO) increased from 3.6 ± 3.2 mm to 32.8 ± 5.4 mm, with no recurrence of ankylosis found during follow-up. In conclusion, this new CDA classification can effectively guide treatment strategies for TMJA patients. Using particular strategies for patients based on specific CDA classifications could provide optimal management to the benefit of TMJA patients.

Differential regulation of blood vessel formation between traumatic temporomandibular joint fibrous ankylosis and bony ankylosis in a sheep model

OBJECTIVES

Clinical and experimental studies show that the etiology of traumatic temporomandibular joint (TMJ) fibrous ankylosis and bony ankylosis are associated with the severity of trauma. However, how the injury severity affects the tissue differentiation is not clear. We tested the hypothesis that angiogenesis affects the outcomes of TMJ trauma, and that enhanced neovascularization after severe TMJ trauma would promote the development of bony ankylosis.

METHODS

Bilateral condylar sagittal fracture and discectomy were performed for each sheep, with the glenoid fossa receiving either severe trauma to induce bony ankylosis or minor trauma to induce fibrous ankylosis. At days 7, 14, 28, and 56 after surgery, total RNA was extracted from the ankylosed callus. Temporal gene expressions of several molecules functionally important for blood vessel formation were studied by real-time PCR.

RESULTS

Histological examination revealed a prolonged hematoma phase and a lack of cartilage formation in fibrous ankylosis. mRNA expression levels of HIF-1α, VEGF, VEGFR2, SDF1, Ang1, Tie2, vWF, CYR61, FGF2, TIMP1, MMP2, and MMP9 were distinctly lower in fibrous ankylosis compared with bony ankylosis at several time points.

CONCLUSIONS

Our study indicates that inhibition of angiogenesis after TMJ trauma might be a promising strategy for preventing bony ankylosis in the future.

Association between the clinical features of and types of temporomandibular joint ankylosis based on a modified classification system

This study aimed to describe the clinical features of different types of traumatic temporomandibular joint (TMJ) ankylosis. Seventy-one patients with 102 ankylosed joints were retrospectively reviewed and categorized into four groups according to the grades of severity: type I, non-bony ankylosis of the joint with almost-normal joint space; type II, lateral bony ankylosis marked by a normal joint space that coexists with a radiolucent line; type III, complete bony ankylosis of the joint characterized by only a radiolucent line; and type IV, extensive bony ankylosis without any radiolucent line. The period of ankylosis, maximal mouth opening (MMO), rate of complications, and histopathological changes were compared among groups. Intergroup comparison showed significant differences in the clinical features of MMO and the incidence of complications (p < 0.05). Younger trauma patients tended to develop more severe types of ankylosis than older patients. Additionally, long post-trauma periods were related to the development of severe ankylosis. MMO was highly negatively correlated with the severity of ankylosis. Significant differences were noted among the four types of ankylosis. Younger trauma patients with long post-trauma periods tended to develop more severe TMJ ankylosis, experience more complications, and face more challenges in treatment than older patients.

High-efficiency generation of induced pluripotent mesenchymal stem cells from human dermal fibroblasts using recombinant proteins

Background

Induced pluripotent mesenchymal stem cells (iPMSCs) are novel candidates for drug screening, regenerative medicine, and cell therapy. However, introduction of transcription factor encoding genes for induced pluripotent stem cell (iPSC) generation which could be used to generate mesenchymal stem cells is accompanied by the risk of insertional mutations in the target cell genome.

Methods

We demonstrate a novel method using an inactivated viral particle to package and deliver four purified recombinant Yamanaka transcription factors (Sox2, Oct4, Klf4, and c-Myc) resulting in reprogramming of human primary fibroblasts. Whole genome bisulfite sequencing was used to analyze genome-wide CpG methylation of human iPMSCs. Western blot, quantitative PCR, immunofluorescence, and in-vitro differentiation were used to assess the pluripotency of iPMSCs.

Results

The resulting reprogrammed fibroblasts show high-level expression of stem cell markers. The human fibroblast-derived iPMSC genome showed gains in DNA methylation in low to medium methylated regions and concurrent loss of methylation in previously hypermethylated regions. Most of the differentially methylated regions are close to transcription start sites and many of these genes are pluripotent pathway associated. We found that DNA methylation of these genes is regulated by the four iPSC transcription factors, which functions as an epigenetic switch during somatic reprogramming as reported previously. These iPMSCs successfully differentiate into three embryonic germ layer cells, both in vitro and in vivo. Following multipotency induction in our study, the delivered transcription factors were degraded, leading to an improved efficiency of subsequent programmed differentiation.

Conclusion

Recombinant transcription factor based reprogramming and derivatization of iPMSC offers a novel high-efficiency approach for regenerative medicine from patient-derived cells.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-016-0358-4) contains supplementary material, which is available to authorized users.

Influence of the lateral pterygoid muscle on traumatic temporomandibular joint bony ankylosis

BACKGROUND

The pathogenesis of traumatic TMJ ankylosis remains unclear. This study aimed to verify the role of the lateral pterygoid muscle in the pathogenesis of traumatic temporomandibular joint (TMJ) bony ankylosis.

METHODS

Eight 6-month-old male sheep were used in this study. Bilateral TMJ osteotomies were performed to induce sagittal fractures of the mandibular condyle. The lateral one-fourth segment of the disc was removed to establish a model of TMJ bony ankylosis. Subsequently, the function of the left and right lateral pterygoid muscles was blocked (experimental group) or maintained (control group), respectively. At 12 weeks postoperatively, animals were sacrificed and TMJ complex samples were evaluated by gross observation, spiral computed tomography (CT), micro-CT, and histological examinations.

RESULTS

Gross observation revealed bony ankylosis in the control TMJs and fibrous adhesions in the experimental TMJs. Spiral CT and micro-CT demonstrated that, compared to the experimental group, the control group showed calcified callus formation in the joint space and roughened articular surfaces after new bone formation, which protruded into the joint space. Maximum mediolateral and anteroposterior condylar diameters were significantly larger in the control group than in the experimental group. Micro-CT also showed that the primary growth orientation of new trabeculae was consistent with the direction of lateral pterygoid traction in the control group, but not in the experimental group. Histological examination showed fibro-osseous ankylosis in the control group, but not in the experimental group.

CONCLUSIONS

The lateral pterygoid simulates the effects of distraction osteogenesis, which is an important factor in the pathogenesis of TMJ bony ankylosis during the healing of sagittal condylar fractures.

Osteoclast Deficiency Contributes to Temporomandibular Joint Ankylosed Bone Mass Formation

Ankylosed bone mass in temporomandibular joint ankylosis (TMJA) is an important factor affecting mouth-opening limitation. However, the mechanism underlying the occurrence of ankylosed bone mass remains unknown. Research has shown that osteoblasts and osteoclasts maintain balance in bone remodeling. Thus, we hypothesized that aberrant osteoclastogenesis and osteogenesis may be involved in the occurrence of ankylosed bone mass in TMJA. In this study, we characterized the osteogenesis of bone marrow stem cells and the osteoclastogenesis of myelomonocyte in clinical specimens of TMJA and normal controls. Results showed that, compared with control bone marrow stem cells, TMJA bone marrow stem cells had lower proliferative and osteogenic capacities. The number of osteoclasts in the ankylosed bone mass group dramatically decreased, and myelomonocyte osteoclastogenic potential was impaired. The RANKL/OPG ratio of the ankylosed bone mass group was lower than that of the control group. Thus, our study suggests that osteoclast deficiency may be an important factor affecting bone mass ankylosis.

Severe bony ankylosis of the temporomandibular joint on one side and contralateral adhesion: A case report

Bony fusion between the mandibular condyle and skull base involves temporomandibular joint (TMJ) bony ankylosis. This condition might originate from trauma, infection, or systemic disease. TMJ adhesion can develop after synovial damage. Both TMJ ankylosis and adhesion lead to functional impairment and pain. Here, we present a case of a 50-year-old female who had bony ankylosis of the right TMJ and adhesion of the left TMJ. She had otitis media in the right ear. A large mass in the right TMJ was observed on computed tomograph. Magnetic resonance image showed a large fused bone mass with normal bone marrow in the right TMJ and flattening of the condyle with a thin disk in the left TMJ. Gap arthroplasty with temporal fascia was performed on the right TMJ, and discectomy, high condylectomy, and coronoidectomy were performed on the left TMJ. During a 2-year follow-up after surgery, the patient had no recurrence.