Dihydroorotate dehydrogenase depletion hampers mitochondrial function and osteogenic differentiation in osteoblasts.

Mutation of the dihydroorotate dehydrogenase (DHODH) gene is responsible for Miller syndrome, which is characterized by craniofacial malformations with limb abnormalities. We previously demonstrated that DHODH was involved in forming a mitochondrial supercomplex and that mutated DHODH led to protein instability, loss of enzyme activity, and increased levels of reactive oxygen species in HeLa cells. To explore the etiology of Miller syndrome in more detail, we investigated the effects of DHODH inhibition in the cells involved in skeletal structure. Dihydroorotate dehydrogenase in MC3T3-E1 cells derived from mouse calvaria osteoblast precursor cells was knocked down by specific small interfering RNAs (siRNAs), and cell proliferation, ATP production, and expression of bone-related genes were investigated in these cells. After depletion of DHODH using specific siRNAs, inhibition of cell proliferation and cell cycle arrest occurred in MC3T3-E1 cells. In addition, ATP production was reduced in whole cells, especially in mitochondria. Furthermore, the levels of runt-related transcription factor 2 (Runx2) and osteocalcin (Ocn) mRNAs were lower in DHODH siRNA-treated cells compared with controls. These data suggest that depletion of DHODH affects the differentiation and maturation of osteoblasts. This study shows that mitochondrial dysfunction by DHODH depletion in osteoblasts can be directly linked to the abnormal bone formation in Miller syndrome.

Transplantation of mesenchymal stem cells ameliorates secondary osteoporosis through interleukin-17-impaired functions of recipient bone marrow mesenchymal stem cells in MRL/lpr mice.

INTRODUCTION: Secondary osteoporosis is common in systemic lupus erythematosus and leads to a reduction in quality of life due to fragility fractures, even in patients with improvement of the primary disorder. Systemic transplantation of mesenchymal stem cells could ameliorate bone loss and autoimmune disorders in a MRL/lpr mouse systemic lupus erythematosus model, but the detailed therapeutic mechanism of bone regeneration is not fully understood. In this study, we transplanted human bone marrow mesenchymal stem cells (BMMSCs) and stem cells from exfoliated deciduous teeth (SHED) into MRL/lpr mice and explored their therapeutic mechanisms in secondary osteoporotic disorders of the systemic lupus erythematosus model mice. METHODS: The effects of systemic human mesenchymal stem cell transplantation on bone loss of MRL/lpr mice were analyzed in vivo and ex vivo. After systemic human mesenchymal stem cell transplantation, recipient BMMSC functions of MRL/lpr mice were assessed for aspects of stemness, osteogenesis and osteoclastogenesis, and a series of co-culture experiments under osteogenic or osteoclastogenic inductions were performed to examine the efficacy of interleukin (IL)-17-impaired recipient BMMSCs in the bone marrow of MRL/lpr mice. RESULTS: Systemic transplantation of human BMMSCs and SHED recovered the reduction in bone density and structure in MRL/lpr mice. To explore the mechanism, we found that impaired recipient BMMSCs mediated the negative bone metabolic turnover by enhanced osteoclastogenesis and suppressed osteoblastogenesis in secondary osteoporosis of MRL/lpr mice. Moreover, IL-17-dependent hyperimmune conditions in the recipient bone marrow of MRL/lpr mice damaged recipient BMMSCs to suppress osteoblast capacity and accelerate osteoclast induction. To overcome the abnormal bone metabolism, systemic transplantation of human BMMSCs and SHED into MRL/lpr mice improved the functionally impaired recipient BMMSCs through IL-17 suppression in the recipient bone marrow and then maintained a regular positive bone metabolism via the balance of osteoblasts and osteoclasts. CONCLUSIONS: These findings indicate that IL-17 and recipient BMMSCs might be a therapeutic target for secondary osteoporosis in systemic lupus erythematosus.

Cryopreserved dental pulp tissues of exfoliated deciduous teeth is a feasible stem cell resource for regenerative medicine.

Human exfoliated deciduous teeth have been considered to be a promising source for regenerative therapy because they contain unique postnatal stem cells from human exfoliated deciduous teeth (SHED) with self-renewal capacity, multipotency and immunomodulatory function. However preservation technique of deciduous teeth has not been developed. This study aimed to evaluate that cryopreserved dental pulp tissues of human exfoliated deciduous teeth is a retrievable and practical SHED source for cell-based therapy. SHED isolated from the cryopreserved deciduous pulp tissues for over 2 years (25-30 months) (SHED-Cryo) owned similar stem cell properties including clonogenicity, self-renew, stem cell marker expression, multipotency, in vivo tissue regenerative capacity and in vitro immunomodulatory function to SHED isolated from the fresh tissues (SHED-Fresh). To examine the therapeutic efficacy of SHED-Cryo on immune diseases, SHED-Cryo were intravenously transplanted into systemic lupus erythematosus (SLE) model MRL/lpr mice. Systemic SHED-Cryo-transplantation improved SLE-like disorders including short lifespan, elevated autoantibody levels and nephritis-like renal dysfunction. SHED-Cryo amended increased interleukin 17-secreting helper T cells in MRL/lpr mice systemically and locally. SHED-Cryo-transplantation was also able to recover osteoporosis bone reduction in long bones of MRL/lpr mice. Furthermore, SHED-Cryo-mediated tissue engineering induced bone regeneration in critical calvarial bone-defect sites of immunocompromised mice. The therapeutic efficacy of SHED-Cryo transplantation on immune and skeletal disorders was similar to that of SHED-Fresh. These data suggest that cryopreservation of dental pulp tissues of deciduous teeth provide a suitable and desirable approach for stem cell-based immune therapy and tissue engineering in regenerative medicine.

Changes in the pharyngeal airway space and hyoid bone position after mandibular setback surgery for skeletal Class III jaw deformity in Japanese women.

INTRODUCTION: The purpose of the study was to examine the changes in stability of pharyngeal airway space (PAS) and hyoid bone position after 2 types of mandibular osteotomies in comparison with a control group. METHODS: The subjects included 46 Japanese women with skeletal Class III malocclusion. Twenty-five patients with mandibular prognathism underwent single-jaw surgery with bilateral sagittal split ramus osteotomy (SSRO), and 21 patients underwent bilateral intraoral vertical ramus osteotomy (IVRO). The control subjects included 30 volunteer women with normal occlusion. The treated subjects were assessed at the beginning of treatment, immediately after surgery, and after postsurgical treatment. RESULTS: The Class III subjects had a significantly wider PAS than did the control subjects. Significant decreases in the lower PAS were observed after orthognathic surgery. The hyoid bone showed upward and forward movement with upward movement of the lower border of the PAS during the postsurgical stage in the SSRO group. In contrast, the anterior border of the PAS and the hyoid bone showed considerable backward movement in the IVRO group. CONCLUSIONS: The posttreatment morphology of the PAS in both Class III groups approached that of the control group. The IVRO group showed a reduction in the airway dimensions, especially during the postsurgical period, which occurred during surgery in the SSRO group.

A 3-dimensional method for analyzing the morphology of patients with maxillofacial deformities.

INTRODUCTION: Traditionally, cephalograms have been used to evaluate a patient's maxillofacial skeleton and facial soft-tissue morphology. However, magnification and distortion of the cephalograms make detailed morphologic analysis difficult in patients with complex deformities. The purpose of this article was to introduce a new method for visualizing deformation and deviation of the maxillofacial skeleton and facial soft tissues. METHODS: Standard 3-dimensional Japanese head models were sized to match the sella-to-nasion distance obtained from 2 patients' (1 man, 1 woman) maxillofacial skeletal images. Then, the scaled standard model was superimposed on each patient's 3-dimensional computed tomography image. RESULTS: This system provided clear shape information independent of size and facilitated the visualization of shape variations in maxillofacial skeletal and facial soft-tissue morphology. CONCLUSIONS: This method will be useful for 3-dimensional morphologic analysis of patients with jaw deformities.

Three-dimensional analysis system for orthognathic surgery patients with jaw deformities.

INTRODUCTION: Traditionally, lateral and frontal cephalograms are used with facial photographs to evaluate a patient's maxillofacial skeletal and facial soft-tissue morphology. However, the enlargement and distortion of 2-dimensional radiography made it difficult to accurately conceptualize the patient's anatomy. The purpose of this article was to introduce a new method for comparing 3-dimensional (3D) standard values of the maxillofacial skeletal and facial soft-tissue morphology before and after orthognathic surgery. METHODS: Normative 3D standard values of the maxillofacial skeletal and facial soft-tissue morphology were calculated from normal women. The pre- and postoperative morphology of one woman who underwent orthognathic surgery was compared with the normative data. RESULTS: This 3D analysis has clinical value to evaluate patients before and after surgical treatment. CONCLUSIONS: This quantitative assessment of 3D maxillofacial morphology can evaluate the area and degree of displacement and rotation of the facial skeleton and facial soft tissues. This method is sufficiently useful for routine clinical applications.

Three-dimensional computer-generated head model reconstructed from cephalograms, facial photographs, and dental cast models.

PURPOSE: Three-dimensional (3D) computer models of the human craniofacial structure have been constructed with computed tomography (CT). However, the high cost of CT and the radiation exposure are drawbacks to this method. Attempts to create a 3D reconstruction from lateral and frontal cephalograms have failed because of problems with magnification, distortion, and limitations of landmark identification, among others. We introduce a new method that creates a standard head model for a patient from anatomic measurement points extracted from x-ray images, facial stereo photographs, and dental casts. MATERIAL: To obtain precise 3D coordinates from cephalograms, several equations were introduced to compensate for radiographic image magnification and distortion. RESULTS: By comparing the constructed model and 3D-CT images, this method proved to be accurate. CONCLUSIONS: It is possible to produce a 3D head model on a personal computer and to view it from any desired angle; this will provide easy-to-understand information for patients and establish a diagnostic or therapeutic method for communication with other health care providers.