ハコツ サイボウ ノ ケイセイ ト カッセイ ニ オヨボス Transforming growth facto-β₁ ノ エイキョウ ニツイテ

Transforming growth factor-β1 (以下TGF-Blと略記する) は、各種細胞の分化、増殖 を調節する多機能な性格を備えたサイトカインである。しかし、破骨細胞の分化、形成 に対するこのサイトカインの役割はいまだに明らかになっていない。 そこで、TGF-β1の破骨細胞による骨吸収に対する影響を調べるため、新生マウス長管 骨より採取した骨組織中の全ての細胞(以下、全前骨細胞と略記する)を象牙片上で培 養した。TGF-β1は0.04-5ng/mlの濃度で、破骨細胞による骨吸収を抑制することがわかっ た。電子顕微鏡による観察では、ミトコンドリアが減少し、液状縁、明帯の形成が弱い ことからも破骨細胞の骨吸収活性の低下が示唆された。 全骨細胞を用いた破骨細胞形成系では、10-8Mの1，1.25-dihydroxyvitamin D3 [以下、1. 25-(OII) 2D3と略記する]とともにTGF-β1を添加すると0.2-1 ng/mlの濃度で破骨細胞形成 を促進することがわかった。次に破骨細胞の形成過程に異種細胞の混入を除いた血液芽 球細胞からの破骨細胞形成系を用いてTGF-β1の破骨細胞形成に対する直接作用について 検討した。意外なことにTGF-β1は、0.2ng/mlより高濃度の群において破骨細胞形成を 抑制した。 近年、破骨細胞の形成には、骨芽細胞が関与していると報告されている。そこで骨芽 細胞を介した間接的な影響を検討するために、骨芽細胞として骨芽細胞様細胞MC3T3-El 細胞を用い、この細胞を1ng/mlのTGF-β1で処理した後に得られる培養上清、細胞外基 質の塩化ナトリウム抽出液を用いて破骨細胞に対する影響を検討したところ、10-8Mの1， 25-(OII)2D3共存下で破骨細胞形成を促進した。 これらのことから、TGF-β1は破骨細胞の活性に対しては、抑制を示す。しかし、破骨 細胞形成に対しては、直接、破骨細胞の形成を抑制するが、間接的には骨芽細胞を介し て促進することが示唆された

Occlusal reconstruction of a patient with ameloblastoma ablation using alveolar distraction osteogenesis: a case report

Background Ameloblastoma is one of the most common benign odontogenic neoplasms. Its surgical excision has the potential to lead to postoperative malocclusion. In this case report, we describe the successful interdisciplinary orthodontic treatment of a patient with ameloblastoma who underwent marginal mandibulectomy. Case presentation A woman of 20-year-old was diagnosed with ameloblastoma, and underwent marginal mandibulectomy when she was 8 years of age. She had an excessive overjet (11.5 mm) and a mild open bite (- 1.5 mm) with a severely resorbed atrophic edentulous ridge in the area around the mandibular left lateral incisor, canine and first premolar. An alveolar bone defect associated with tumor resection was regenerated by vertical distraction osteogenesis (DO). Subsequently, 3 dental implants were placed into the reconstructed mandible. Orthodontic treatment using implant-anchored mechanics provided a proper facial profile with significantly improved occlusal function. The occlusion appeared stable for a 7-year retention period. Conclusions These results suggest that surgically assisted and implant anchored-orthodontic approaches might be effective for the correction of such malocclusions

Orthodontic Treatment of a Patient with Bilateral Congenitally Missing Maxillary Canines: The Effects of First Premolar Substitution on the Functional Outcome

Permanent canines are thought to play a pivotal role in obtaining an ideal occlusion. Dentists occasionally encounter patients who lack canines and are therefore missing a key to harmonious guidance during functional mandibular excursions. This case report describes the substitution of maxillary first premolars for congenitally missing canines in the context of an orthodontic treatment plan. A boy, age 10 years and 11 months, with a chief complaint of crooked teeth was diagnosed with Class II division 2 malocclusion associated with a high mandibular plane angle and deep overbite. A stable occlusion with a satisfactory facial profile and functional excursions without interference were achieved after a comprehensive two-stage orthodontic treatment process. The resulting occlusion and satisfactory facial profile were maintained for 12 months. These results indicate that substituting the first premolars for the canines is an effective option in treating patients with missing canines while maintaining functional goals

Primary cultures of chick osteocytes retain functional gap junctions between osteocytes and between osteocytes and osteoblasts

The inaccessibility of osteocytes due to their embedment in the calcified bone matrix in vivo has precluded direct demonstration that osteocytes use gap junctions as a means of intercellular communication. In this article, we report successfully isolating primary cultures of osteocytes from chick calvaria, and, using anti-connexin 43 immunocytochemistry, demonstrate gap junction distribution to be comparable to that found in vivo. Next, we demonstrate the functionality of the gap junctions by (1) dye coupling studies that showed the spread of microinjected Lucifer Yellow from osteoblast to osteocyte and between adjacent osteocytes and (2) analysis of fluorescence replacement after photobleaching (FRAP), in which photobleaching of cells loaded with a membrane-permeable dye resulted in rapid recovery of fluorescence into the photobleached osteocyte, within 5 min postbleaching. This FRAP effect did not occur when cells were treated with a gap junction blocker (18 alpha-glycyrrhetinic acid), but replacement of fluorescence into the photobleached cell resumed when it was removed. These studies demonstrate that gap junctions are responsible for intercellular communication between adjacent osteocytes and between osteoblasts and osteocytes. This role is consistent with the ability of osteocytes to respond to and transmit signals over long distances while embedded in a calcified matrix. </p

Modification of Dentofacial Growth Associated with Goldenhar Syndrome

The rare developmental defect, Goldenhar syndrome is characterized by complex craniofacial and dentofacial anomalies. Here we describe the successful orthodontic treatment of a 5-year-old Japanese Goldenhar syndrome patient with mild facial asymmetry, right microtia, right-side hearing loss, and tongue-thrusting by a modification of dentofacial growth using a non-surgical orthopedic treatment approach. Improvement of the vertical discrepancies on the affected side and canted occlusal plane as well as mandibular deviation were achieved with a functional orthopaedic approach. Stable and acceptable occlusion were obtained over the 32-month post-retention period. A non-surgical orthodontic treatment approach offers satisfactory facial aesthetic outcomes in Goldenhar syndrome

Camouflage Treatment for Skeletal Maxillary Protrusion and Lateral Deviation with Classic-Type Ehlers-Danlos Syndrome

We herein report the case of a 19-year-old female with a transverse discrepancy, skeletal Class II malocclusion, severe crowding with concerns of classic-type Ehlers-Danlos syndrome (EDS), aesthetics problems and functional problems. The main characteristics of classic EDS are loose-jointedness and fragile, easily bruised skin that heals with peculiar “cigarette-paper” scars. The anteroposterior and transverse skeletal discrepancies can generally be resolved by maxilla repositioning and mandibular advancement surgery following pre-surgical orthodontic treatment. However, this patient was treated with orthodontic camouflage but not orthognathic surgery because of the risks of skin bruising, poor healing and a temporomandibular disorder. A satisfactory dental appearance and occlusion were achieved after camouflage treatment with orthodontic anchor screws and the use of Class II elastics, including the preservation of the stomatognathic functions. Acceptable occlusion and dentition were maintained after a two-year retention period. This treatment strategy of orthodontic camouflage using temporary anchorage, such as anchor screws and Class II elastics, may be a viable treatment option for skeletal malocclusion patients with EDS

Maxillary Advancement for Unilateral Crossbite in a Patient with Sleep Apnea Syndrome

This article reports the case of a 44-year-old male with skeletal Class III, Angle Class III malocclusion and unilateral crossbite with concerns about obstructive sleep apnea syndrome (OSAS), esthetics and functional problems. To correct the skeletal deformities, the maxilla was anteriorly repositioned by employing LeFort I osteotomy following pre-surgical orthodontic treatment, because a mandibular setback might induce disordered breathing and cause OSAS. After active treatment for 13 months, satisfactory occlusion was achieved and an acceptable facial and oral profile was obtained. In addition, the apnea hypopnea index (AHI) decreased from 18.8 preoperatively to 10.6 postoperatively. Furthermore, after a follow-up period of 7 months, the AHI again significantly decreased from 10.6 to 6.2. In conclusion, surgical advancement of the maxilla using LeFort I osteotomy has proven to be useful in patients with this kind of skeletal malocclusion, while preventing a worsening of the OSAS

Quantitative Evaluation of Osteocyte Morphology and Bone Anisotropic Extracellular Matrix in Rat Femur

Osteocytes are believed to play a crucial role in mechanosensation and mechanotransduction which are important for maintenance of mechanical integrity of bone. Recent investigations have revealed that the preferential orientation of bone extracellular matrix (ECM) mainly composed of collagen fibers and apatite crystallites is one of the important determinants of bone mechanical integrity. However, the relationship between osteocytes and ECM orientation remains unclear. In this study, the association between ECM orientation and anisotropy in the osteocyte lacuno-canalicular system, which is thought to be optimized along with the mechanical stimuli, was investigated using male rat femur. The degree of ECM orientation along the femur longitudinal axis was significantly and positively correlated with the anisotropic features of the osteocyte lacunae and canaliculi. At the femur middiaphysis, there are the osteocytes with lacunae that highly aligned along the bone long axis (principal stress direction) and canaliculi that preferentially extended perpendicular to the bone long axis, and the highest degree of apatite c-axis orientation along the bone long axis was shown. Based on these data, we propose a model in which osteocytes can change their lacuno-canalicular architecture depending on the mechanical environment so that they can become more susceptible to mechanical stimuli via fluid flow in the canalicular channel.Ishimoto T., Kawahara K., Matsugaki A., et al. Quantitative Evaluation of Osteocyte Morphology and Bone Anisotropic Extracellular Matrix in Rat Femur. Calcified Tissue International, 109, 4, 434. https://doi.org/10.1007/s00223-021-00852-1

Role of intracellular Ca2+–based mechanotransduction of human periodontal ligament fibroblasts

Human periodontal ligament (hPDL) fibroblasts are thought to receive mechanical stress (MS) produced by orthodontic tooth movement, thereby regulating alveolar bone remodeling. However, the role of intracellular calcium ([Ca2+]i)‐based mechanotransduction is not fully understood. We explored the MS‐induced [Ca2+]i responses both in isolated hPDL fibroblasts and in intact hPDL tissue and investigated its possible role in alveolar bone remodeling. hPDL fibroblasts were obtained from healthy donors' premolars that had been extracted for orthodontic reasons. The oscillatory [Ca2+]i activity induced by static compressive force was measured by a live‐cell Ca2+ imaging system and evaluated by several feature extraction method. The spatial pattern of cell‐cell communication was investigated by Moran's I , an index of spatial autocorrelation and the gap junction (GJ) inhibitor. The Ca2+‐transporting ionophore A23187 was used to further investigate the role of [Ca2+]i up‐regulation in hPDL cell behavior. hPDL fibroblasts displayed autonomous [Ca2+]i responses. Compressive MS activated this autonomous responsive behavior with an increased percentage of responsive cells both in vitro and ex vivo . The integration, variance, maximum amplitude, waveform length, and index J in the [Ca2+]i responses were also significantly increased, whereas the mean power frequency was attenuated in response to MS. The increased Moran's I after MS indicated that MS might affect the pattern of cell‐cell communication via GJs. Similar to the findings of MS‐mediated regulation, the A23187‐mediated [Ca2+]i uptake resulted in the up‐regulation of receptor activator of NF‐κB ligand (Rankl) and Sost along with increased sclerostin immunoreactivity, suggesting that [Ca2+]i signaling networks may be involved in bone remodeling. In addition, A23187‐treated hPDL fibroblasts also showed the suppression of osteogenic differentiation and mineralization. Our findings suggest that augmented MS‐mediated [Ca2+]i oscillations in hPDL fibroblasts enhance the production and release of bone regulatory signals via Rankl/Osteoprotegerin and the canonical Wnt/β‐catenin pathway as an early process in tooth movement–initiated alveolar bone remodeling.—Ei Hsu Hlaing, E., Ishihara, Y., Wang, Z., Odagaki, N., Kamioka, H. Role of intracellular Ca2+‐based mechanotransduction of human periodontal ligament fibroblasts. FASEB J. 33, 10409–10424 (2019)