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Background/purpose Conditioned media of cultured mesenchymal stem cells (MSCs) contain numerous kinds of secretomes such as cytokines and chemokines. We previously reported that conditioned media of bone marrow-derived MSCs (MSC-CM) promote bone formation. Recently, macrophage phenotype switching from the pro-inflammatory M1 type to the anti-inflammatory M2 type has been reported to be an important phenomenon during tissue regeneration. Some studies reported that this phenotype switching is regulated by secretomes. In this study, macrophage phenotype during bone formation by MSC-CM was investigated. Materials and methods Human MSCs (hMSCs) were cultured in serum-free medium and the collected medium was defined as MSC-CM. Macrophage-related gene expressions in hMSCs cultured with MSC-CM were evaluated by quantitative real-time polymerase chain reaction. MSC-CM was implanted and the evaluations by micro-CT and immunohistochemistry were performed using a rat the calvaria bone defect model. Results Two and four weeks after implantation, the MSC-CM group demonstrated enhanced bone regeneration. Gene expressions of C–C motif chemokine 2 (CCL2), colony-stimulating factor 2 (CSF2) and CD163 was significantly upregulated in cells exposed to MSC-CM. Immunohistochemical staining revealed that iNOS-positive M1 macrophages were reduced, while CD204-positive M2 macrophages were increased in the MSC-CM group at 72 h after implantation, and the M2/M1 ratio increased only in the MSC-CM group. Conclusion MSC-CM enhances macrophage migration and induces M1 to M2 type macrophage switching at an early stage of osteogenesis. Such phenotype switching provides a favorable environment for angiogenesis, cellular migration, and osteogenesis and contributes to MSC-CM-induced early bone formation.

BackgroundThe free vascularized fibula flap presents many advantages such as sufficient length of the bony segment, good vascularization, better quality of the bone, and a long vascular pedicle, but it is also associated with some disadvantages with regard to prosthetic rehabilitation because of its limited height. Improvement in bone height is necessary for ideal dental implant treatment of reconstructed mandibles.Case presentationFor two squamous cell carcinoma patients, mandibular bone reconstruction was performed secondarily with the peroneal flap after tumor resection. Since the bone height was insufficient at the time of implant treatment, occlusion reconstruction by dental implant was performed after vertical distraction osteogenesis.ConclusionsVertical distraction osteogenesis is a suitable treatment option for alveolar ridge deficiency resulting from fibula transplantation for mandibular reconstruction following tumor surgery.

Condylar resorption (CR) after surgical orthognathic treatment is defined as dysfunctional remodeling of the temporomandibular joint manifested by morphological changes with decreased condylar head volume that cause occlusal and esthetic changes. Although both conservative and surgical treatment strategies have been employed for the treatment of CR, effective procedures have not been established till date. In this study, the effects of MSC-CM on CR were investigated. Bone marrow-derived MSCs of rats (rMSCs) were cultured until 80% confluent, cultured in serum-free conditioned medium for 48 h; the collected medium was defined as MSC-CM. Osteogenesis, chondrogenesis, and angiogenesis-related gene expression in rMSCs cultured with MSC-CM was evaluated by quantitative real-time polymerase chain reaction. A rat CR model was used for animal studies, in which CR occurred after mandibular distraction osteogenesis for 10 days. MSC-CM was injected via the tail vein and quantitative and qualitative evaluations were performed by micro-computed tomography (micro-CT) and histology. MSC-CM enhanced osteogenesis-, chondrogenesis-, and angiogenesis-related gene expression in rMSCs. Micro-CT showed CR in control groups; however, it was observed to be improved in the MSC-CM group. Histologically, an enlarged cartilage layer was seen in the MSC-CM group, while cartilage layers had almost thinned or disappeared in control groups. These results indicate that MSC-CM improved CR.

Clinical analysis was performed for 1,448 patients with jaw deformities who had undergone orthognathic surgery in our hospital over the past 48 years. The patients included 473 males and 975 females with a mean age at the time of operation of 22 years (range : 12-55 years) .About 90% of the patients were under 30 years of age.

These results suggest that bone mass and architecture strongly affect the tolerance to the overloading and adaptation with bone apposition in condylar resorption site.

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Septic arthritis of the temporomandibular joint (TMJ) is a rare disease that is characterized by preauricular pain, edema, malocclusion, trismus and abscess formation in the TMJ region. An 85-year-old male visited our hospital with the complaint of left-sided TMJ swelling, pain and trismus. Septic arthritis of the left TMJ was diagnosed on the basis of considerable elevation of CRP (Creactive proteins) and CT imaging findings. The patient was treated with oral Faropenem at 450 mg daily, but CRP increased three days after the initial visit. He was hospitalized and treated with intravenous administration of cefazolin at 2 g and clindamycin at 1.2 g daily for six days. Propionibacterium species and Veillonella species grew in a culture of the joint aspirate, but there was no apparent source of infection. After acute infectious symptoms had passed, the patient was treated with oral amoxicillin at 750 mg daily for eight weeks and was instructed to do jaw opening exercise. The patient was discharged on the 11th hospital day. After three weeks of the hospital discharge, the patient healed completely. To avoid serious complications, clinicians should include septic arthritis of the TMJ in the differential diagnosis of preauricular pain, trismus and swelling.