Masticatory muscle tendon-aponeurosis hyperplasia that was initially misdiagnosed for polymyositis: a case report and review of the literature.

BACKGROUND: Masticatory muscle tendon-aponeurosis hyperplasia (MMTAH) is a relatively newly identified clinical condition that manifests as trismus with a square-shaped mandible. Herein, we report a case of MMATH that was initially misdiagnosed for polymyositis due to trismus and simultaneous lower limb pain, with literature review. CASE PRESENTATION: A 30-year-old woman had a history of lower limb pain after exertion for 2 years. Initial physical examination had been performed at the Department of General Medicine in our hospital. There was also redness in the hands and fingers. Although polymyositis was suspected, it was denied. The patient visited our department for right maxillary wisdom tooth extraction. Clinical examination revealed that the patient had a square-shaped mandible. The maximal mouth opening was 22 mm. There was no temporomandibular joint pain at the time of opening. Furthermore, there was awareness of clenching while working. Panoramic radiography revealed developed square mandibular angles with flattened condyles. Computed tomography showed enlarged masseter muscles with high-density areas around the anterior and lateral fascia. Magnetic resonance imaging also showed thickened tendons and aponeuroses on the anterior surface and inside bilateral masseter muscles. Finally, the patient was diagnosed with MMTAH. Bilateral aponeurectomy of the masseter muscles with coronoidectomy and masseter muscle myotomy was performed under general anesthesia. The maximum opening during surgery was 48 mm. Mouth opening training was started on day 3 after surgery. Histopathological examination of the surgical specimen showed that the muscle fibers were enlarged to 60 µm. Immunohistochemistry testing for calcineurin, which was associated with muscle hypertrophy due to overload in some case reports, showed positive results. Twelve months after surgery, the mouth self-opening and forced opening were over 35 mm and 44 mm, respectively. CONCLUSIONS: Herein, we report a case of MMATH. Lower limb pain due to prolonged standing at work and overload due to clenching were considered risk factors for symptoms onset of MMATH.

Prognostic value of preoperative systemic inflammatory response as a prognostic indicator in patients with early-stage oral squamous cell carcinoma.

To determine the usefulness of lymphocyte-to-monocyte ratio (LMR), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and inflammatory response biomarker (IRB) score for predicting disease-specific survival and delayed cervical lymph node metastasis in early-stage oral squamous cell carcinoma (OSCC). We retrospectively analyzed 72 patients with early-stage OSCC. Receiver operating characteristic curve analysis was used to determine the cutoff values for LMR, NLR, and PLR. IRB score was determined as follows: high LMR, high NLR, and low PLR, which were each rated as 1. These scores were added to obtain IRB score (range: 0-3). From univariate analysis, gender, poor mode of invasion, and high IRB score were identified as significant risk factors for disease-specific survival. However, there were no independent factors for poor prognosis in multivariate analysis. On the other hand, for delayed cervical lymph node metastasis, poor mode of invasion, low LMR, high NLR, high PLR, and high IRB score were identified as significant risk factors from univariate analysis, and in multivariate analysis, poor mode of invasion and high IRB score were confirmed as independent risk factors. IRB score and mode of invasion are potentially independent risk factors for delayed cervical lymph node metastasis in early-stage OSCC.

Dual near-infrared II laser modulates the cellular redox state of T cells and augments the efficacy of cancer immunotherapy.

Immunotherapy, including immune checkpoint inhibitors, has revolutionized cancer treatment, but only a minor fraction of patients shows durable responses. A new approach to overcome this limitation is yet to be identified. Recently, we have shown that photobiomodulation (PBM) with near-infrared (NIR) light in the NIR-II window reduces oxidative stress and supports the proliferation of CD8+ T cells, suggesting that PBM with NIR-II light could augment anti-cancer immunity. Here, we report a novel approach to support tumor-infiltrating CD8+ T cells upon PBM with NIR-II laser with high tissue penetration depth. Brief treatments of a murine model of breast cancer with dual 1064 and 1270 nm lasers reduced the expression of the programmed cell death protein 1 (PD-1) in CD8+ T cells in a syngeneic mouse model of breast cancer. The direct effect of the NIR-II laser treatment on T cells was confirmed by the enhanced tumor growth delay by the adoptive transfer of laser-treated CD8+ T cells ex vivo against a model tumor antigen. We further demonstrated that specific NIR-II laser parameters augmented the effect of the immune checkpoint inhibitor on tumor growth. PBM with NIR-II light augments the efficacy of cancer immunotherapy by supporting CD8+ T cells. Unlike the current immunotherapy with risks of undesirable drug-drug interactions and severe adverse events, the laser is safe and low-cost. It can be broadly combined with other therapy without modification to achieve clinical significance. In addition, our study established a path to develop a novel laser-based therapy to treat cancer effectively.

Near-infrared II photobiomodulation augments nitric oxide bioavailability via phosphorylation of endothelial nitric oxide synthase.

There is solid evidence of the beneficial effect of photobiomodulation (PBM) with low-power near-infrared (NIR) light in the NIR-I window in increasing bioavailable nitric oxide (NO). However, it is not established whether this effect can be extended to NIR-II light, limiting broader applications of this therapeutic modality. Since we have demonstrated PBM with NIR laser in the NIR-II window, we determined the causal relationship between NIR-II irradiation and its specific biological effects on NO bioavailability. We analyzed the impact of NIR-II irradiation on NO release in cultured human endothelial cells using a NO-sensitive fluorescence probe and single-cell live imaging. Two distinct wavelengths of NIR-II laser (1064 and 1270 nm) and NIR-I (808 nm) at an irradiance of 10 mW/cm2 induced NO release from endothelial cells. These lasers also enhanced Akt phosphorylation at Ser 473, endothelial nitric oxide synthase (eNOS) phosphorylation at Ser 1177, and endothelial cell migration. Moreover, the NO release and phosphorylation of eNOS were abolished by inhibiting mitochondrial respiration, suggesting that Akt activation caused by NIR-II laser exposure involves mitochondrial retrograde signaling. Other inhibitors that inhibit known Akt activation pathways, including a specific inhibitor of PI3K, Src family PKC, did not affect this response. These two wavelengths of NIR-II laser induced no appreciable NO generation in cultured neuronal cells expressing neuronal NOS (nNOS). In short, NIR-II laser enhances bioavailable NO in endothelial cells. Since a hallmark of endothelial dysfunction is suppressed eNOS with concomitant NO deficiency, NIR-II laser technology could be broadly used to restore endothelial NO and treat or prevent cardiovascular diseases.

Migration and phenotype switching of macrophages at early-phase of bone-formation by secretomes from bone marrow derived mesenchymal stem cells using rat calvaria bone defect model.

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.

Near-Infrared Fluorescence Imaging of Carotid Plaques in an Atherosclerotic Murine Model.

Successful imaging of atherosclerosis, one of the leading global causes of death, is crucial for diagnosis and intervention. Near-infrared fluorescence (NIRF) imaging has been widely adopted along with multimodal/hybrid imaging systems for plaque detection. We evaluate two macrophage-targeting fluorescent tracers for NIRF imaging (TLR4-ZW800-1C and Feraheme-Alexa Fluor 750) in an atherosclerotic murine cohort, where the left carotid artery (LCA) is ligated to cause stenosis, and the right carotid artery (RCA) is used as a control. Imaging performed on dissected tissues revealed that both tracers had high uptake in the diseased vessel compared to the control, which was readily visible even at short exposure times. In addition, ZW800-1C's renal clearance ability and Feraheme's FDA approval puts these two tracers in line with other NIRF tracers such as ICG. Continued investigation with these tracers using intravascular NIRF imaging and larger animal models is warranted for clinical translation.

Brief exposure of skin to near-infrared laser augments early vaccine responses.

Rapid establishment of herd immunity with vaccination is effective to combat emerging infectious diseases. Although the incorporation of adjuvant and intradermal (ID) injection could augment early responses to the vaccine, the current chemical or biological adjuvants are inappropriate for this purpose with their side effects and high reactogenicity in the skin. Recently, a near-infrared (NIR) laser has been shown to augment the immune response to ID vaccination and could be alternatively used for mass vaccination programs. Here, we determined the effect of NIR laser as well as licensed chemical adjuvants on the immunogenicity 1, 2, and 4 weeks after ID influenza vaccination in mice. The NIR laser adjuvant augmented early antibody responses, while the widely used alum adjuvant induced significantly delayed responses. In addition, the oil-in-water and alum adjuvants, but not the NIR laser, elicited escalated TH2 responses with allergenic immunoglobulin E (IgE) responses. The effect of the NIR laser was significantly suppressed in the basic leucine zipper transcription factor ATF-like 3 (Batf3) knockout mice, suggesting a critical role of the cluster of differentiation 103+ (CD103)+ dendritic cells. The current preliminary study suggests that NIR laser adjuvant is an alternative strategy to chemical and biological agents to timely combat emerging infectious diseases. Moreover, its immunomodulatory property could be used to enhance the efficacy of immunotherapy for allergy and cancer.

Other iatrogenic immunodeficiency-associated lymphoproliferative disorders in the oral cavity: a clinicopathologic study of 4 cases and literature review.

OBJECTIVES: Other iatrogenic immunodeficiency-associated lymphoproliferative disorders (OI-LPD) have been reported as one of the adverse effects of immunosuppressive therapy. The aim of this study was to describe the clinicopathologic and immunohistochemical features of OI-LPD in the oral cavity. STUDY DESIGN: Immunohistochemistry was performed to describe the immunohistochemical features in our 4 cases. The results were analyzed along with 62 cases of oral OI-LPD in the English and Japanese literature to define clinical and pathologic characteristic features. RESULTS: In our immunohistochemical analysis, Epstein-Barr virus (EBV)-positive OI-LPD showed a higher percentage of mouse double minute 2-positive cells than EBV-negative samples. A literature survey revealed that OI-LPD (including the present cases) arises primarily in the gingiva, followed by the tongue, and usually occurs with a male-to-female ratio of 1:1.9. The rate of EBV positivity was 93.8%. Further, 31 of 66 patients had osteonecrosis of the jaw and 24 of 31 patients had taken multiple immunosuppressive drugs in combination. CONCLUSIONS: We can therefore conclude that the overexpression of mouse double minute 2 in OI-LPD is associated with EBV infection, and the combination of multiple immunosuppressive drugs may be a risk factor for osteonecrosis of the jaw.

Conditioned medium from mesenchymal stem cells improves condylar resorption induced by mandibular distraction osteogenesis in a rat model.

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.

Peripheral Nerve Regeneration in a Novel Rat Model of Dysphagia.

The superior laryngeal nerve (SLN) is known to play an essential role in the laryngeal reflex and swallowing. Damage to the SLN causes difficulty swallowing, that is, dysphagia. We successfully developed a novel rat model of dysphagia by SLN injury, in which we could evaluate the neuroregenerative capacity of stem cell from human exfoliated deciduous teeth (SHED). The dysphagic rats exhibit weight loss and altered drinking patterns. Furthermore, SLN injury induces a delayed onset of the swallowing reflex and accumulation of laryngeal debris in the pharynx. This rat model was used to evaluate the systemic application of SHED-conditioned medium (SHED-CM) as a therapeutic candidate for dysphagia. We found that SHED-CM promoted functional recovery and significant axonal regeneration in SLNs through the polarization shift of macrophages from activated inflammatory macrophages (M1) to anti-inflammatory macrophages (M2) and angiogenesis. This chapter describes the establishment of SLN-injury induced dysphagia rat model and the preparation and application of SHED-CM.

Rapid and Selective Targeting of Heterogeneous Pancreatic Neuroendocrine Tumors.

Design of tissue-specific contrast agents to delineate tumors from background tissues is a major unmet clinical need for ultimate surgical interventions. Bioconjugation of fluorophore(s) to a ligand has been mainly used to target overexpressed receptors on tumors. However, the size of the final targeted ligand can be large, >20 kDa, and cannot readily cross the microvasculature to meet the specific tissue, resulting in low targetability with a high background. Here, we report a small and hydrophilic phenoxazine with high targetability and retention to pancreatic neuroendocrine tumor. This bioengineered fluorophore permits sensitive detection of ultrasmall (<0.5 mm) ectopic tumors within a few seconds after a single bolus injection, highlighting every tumor in the pancreas from the surrounding healthy tissues with reasonable half-life. The knowledge-based approach and validation used to develop structure-inherent tumor-targeted fluorophores have a tremendous potential to improve treatment outcome by providing definite tumor margins for image-guided surgery.

High-throughput single-cell live imaging of photobiomodulation with multispectral near-infrared lasers in cultured T cells.

SIGNIFICANCE: Photobiomodulation is a well-established therapeutic modality. However, the mechanism of action is poorly understood, due to lack of research in the causal relationship between the near-infrared (NIR) light irradiation and its specific biological effects, hindering broader applications of this technology. AIM: Since biological chromophores typically show several absorption peaks, we determined whether specific effects of photobiomodulation are induced with a combination of two wavelengths at a certain range of irradiance only, rather than a single wavelength of NIR light. APPROACH: In order to analyze a wide array of combinations of multispectral NIR light at various irradiances efficiently, we developed a new optical platform equipped with two distinct wavelengths of NIR lasers by high-throughput multiple dosing for single-cell live imaging. Two wavelengths of 1064 and 1270 nm were selected based on their photobiomodulatory effects reported in the literature. RESULTS: A specific combination of wavelengths at low irradiances (250 to 400 mW / cm2 for 1064 nm and 55 to 65 mW / cm2 for 1270 nm) modulates mitochondrial retrograde signaling, including intracellular calcium and reactive oxygen species in T cells. The time-dependent density functional theory computation of binding of nitric oxide (NO) to cytochrome c oxidase indicates that the illumination with NIR light could result in the NO release, which might be involved in these changes. CONCLUSIONS: This optical platform is a powerful tool to study causal relationship between a specific parameter of NIR light and its biological effects. Such a platform is useful for a further mechanistic study on not only photobiomodulation but also other modalities in photomedicine.

Exosomes from conditioned media of bone marrow-derived mesenchymal stem cells promote bone regeneration by enhancing angiogenesis.

Growth factors in serum-free conditioned media from human bone marrow-derived mesenchymal stem cells (MSC-CM) are known to be effective in bone regeneration. However, the secretomes in MSC-CM that act as active ingredients for bone regeneration, as well as their mechanisms, remains unclear. Exosomes, components of MSC-CM, provide the recipient cells with genetic information and enhance the recipient cellular paracrine stimulation, which contributes to tissue regeneration. We hypothesized that MSC-CM-derived exosomes (MSC-Exo) promoted bone regeneration, and that angiogenesis was a key step. Here, we prepared an MSC-Exo group, MSC-CM group, and Exo-antiVEGF group (MSC-Exo with angiogenesis inhibitor), and examined the osteogenic and angiogenic potential in MSCs. Furthermore, we used a rat model of calvaria bone defect and implanted each sample to evaluate bone formation weekly, until week 4 after treatment. Results showed that MSC-Exo enhanced cellular migration and osteogenic and angiogenic gene expression in MSCs compared to that in other groups. In vivo, early bone formation by MSC-Exo was also confirmed. Two weeks after implantation, the newly formed bone area was 31.5 ± 6.5% in the MSC-Exo group while those in the control and Exo-antiVEGF groups were 15.4 ± 4.4% and 8.7 ± 1.1%, respectively. Four weeks after implantation, differences in the area between the MSC-Exo group and the Exo-antiVEGF or control groups were further broadened. Histologically, notable accumulation of osteoblast-like cells and vascular endothelial cells was observed in the MSC-Exo group; however, fewer cells were found in the Exo-antiVEGF and control groups. In conclusion, MSC-Exo promoted bone regeneration during early stages, as well as enhanced angiogenesis. Considering the tissue regeneration with transplanted cells and their secretomes, this study suggests that exosomes might play an important role, especially in angiogenesis.

Real-Time Imaging of Vaccine Biodistribution Using Zwitterionic NIR Nanoparticles.

Efficient and timely delivery of vaccine antigens to the secondary lymphoid tissue is crucial to induce protective immune responses by vaccination. However, determining the longitudinal biodistribution of injected vaccines in the body has been a challenge. Here, the near-infrared (NIR) fluorescence imaging is reported that can efficiently enable the trafficking and biodistribution of vaccines in real time. Zwitterionic NIR fluorophores are conjugated on the surface of model vaccines and tracked the fate of bioconjugated vaccines after intradermal administration. Using an NIR fluorescence imaging system, it is possible to obtain time-course imaging of vaccine trafficking through the lymphatics, observing notable uptake in lymph nodes with minimal nonspecific tissue interactions. Flow cytometry analysis confirmed that the uptake in lymph nodes by antigen presenting cells was highly dependent on the hydrodynamic diameter of vaccines. These results demonstrate that the combination of a real-time NIR fluorescence imaging system and zwitterionic fluorophores is a powerful tool to determine the fate of vaccine antigens. Since such non-specific vaccine uptake causes serious adverse reactions, this method is not only useful for optimization of vaccine design, but also for safety evaluation of clinical vaccine candidates.

Design of a Randomized Controlled Clinical Study of tissue-engineered osteogenic materials using bone marrow-derived mesenchymal cells for Maxillomandibular bone defects in Japan: the TEOM study protocol.

BACKGROUND: Maxillomandibular bone defects arise from maxillofacial injury or tumor/cyst removal. While the standard therapy for bone regeneration is transplantation with autologous bone or artificial bone, these therapies are still unsatisfactory. Autologous bone harvesting is invasive and occasionally absorbed at the implanted site. The artificial bone takes a long time to ossify and it often gets infected. Therefore, we have focused on regenerative therapy consisting of autologous bone marrow-derived mesenchymal cells (BM-MSCs), which decreases the burden on patients. Based on our previous research in patients with maxillomandibular bone defects or alveolar bone atrophy using a mixture of BM-MSCs, platelet-rich plasma (PRP), thrombin, and calcium, we confirmed the efficacy and acceptable safety profile of this treatment. In this investigator-initiated clinical study (the TEOM study), we intended to add ß-tricalcium phosphate (ß-TCP) owing to large defect with patients. The TEOM study aimed to evaluate the efficacy and safety of bone regeneration using mixtures of BM-MSCs in patients with bone defects resulting from maxillofacial injury, and tumor/cyst removal in the maxillomandibular region. METHODS: The TEOM study is an open-label, single-center, randomized controlled study involving a total of 83 segments by the Fédération Dentaire Internationale numbering system in maxillomandibular bone defects that comprise over 1/3 of the maxillomandibular area with a remaining bone height of ≤10 mm. The primary endpoint is rate of procedure sites with successful bone regeneration defined as a computed tomography (CT) value of more than 400 and a bone height of more than 10 mm. Our specific hypothesis is that the number of required regions was calculated assuming that the rate of procedure sites with successful bone regeneration is similar and the non-inferiority margin is 15.0%. DISCUSSION: The TEOM study is the first randomized controlled study of regenerative treatment using BM-MSCs for large maxillomandibular bone defects. We will evaluate the efficacy and safety in this study to provide an exploratory basis for the necessity of BM-MSCs for these patients. TRIAL REGISTRATION: This trial was registered at the University Hospital Medical information Network Clinical Trials Registry (UMIN-CTR Unique ID: UMIN000020398; Registration Date: Jan 15, 2016; URL: https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000016543 ).

Dental pulp-derived stem cell conditioned medium to regenerate peripheral nerves in a novel animal model of dysphagia.

In nerve regeneration studies, various animal models are used to assess nerve regeneration. However, because of the difficulties in functional nerve assessment, a visceral nerve injury model is yet to be established. The superior laryngeal nerve (SLN) plays an essential role in swallowing. Although a treatment for SLN injury following trauma and surgery is desirable, no such treatment is reported in the literature. We recently reported that stem cells derived from human exfoliated deciduous teeth (SHED) have a therapeutic effect on various tissues via macrophage polarization. Here, we established a novel animal model of SLN injury. Our model was characterized as having weight loss and drinking behavior changes. In addition, the SLN lesion caused a delay in the onset of the swallowing reflex and gain of laryngeal residue in the pharynx. Systemic administration of SHED-conditioned media (SHED-CM) promoted functional recovery of the SLN and significantly promoted axonal regeneration by converting of macrophages to the anti-inflammatory M2 phenotype. In addition, SHED-CM enhanced new blood vessel formation at the injury site. Our data suggest that the administration of SHED-CM may provide therapeutic benefits for SLN injury.

Brief Exposure of Skin to Near-Infrared Laser Modulates Mast Cell Function and Augments the Immune Response.

The treatment of skin with a low-power continuous-wave (CW) near-infrared (NIR) laser prior to vaccination is an emerging strategy to augment the immune response to intradermal vaccine, potentially substituting for chemical adjuvant, which has been linked to adverse effects of vaccines. This approach proved to be low cost, simple, small, and readily translatable compared with the previously explored pulsed-wave medical lasers. However, little is known on the mode of laser-tissue interaction eliciting the adjuvant effect. In this study, we sought to identify the pathways leading to the immunological events by examining the alteration of responses resulting from genetic ablation of innate subsets including mast cells and specific dendritic cell populations in an established model of intradermal vaccination and analyzing functional changes of skin microcirculation upon the CW NIR laser treatment in mice. We found that a CW NIR laser transiently stimulates mast cells via generation of reactive oxygen species, establishes an immunostimulatory milieu in the exposed tissue, and provides migration cues for dermal CD103+ dendritic cells without inducing prolonged inflammation, ultimately augmenting the adaptive immune response. These results indicate that use of an NIR laser with distinct wavelength and power is a safe and effective tool to reproducibly modulate innate programs in skin. These mechanistic findings would accelerate the clinical translation of this technology and warrant further explorations into the broader application of NIR lasers to the treatment of immune-related skin diseases.

Cytokine Mixtures Mimicking Secretomes From Mesenchymal Stem Cells Improve Medication-Related Osteonecrosis of the Jaw in a Rat Model.

Recently, several studies have demonstrated that intravenous administration of mesenchymal stem cells (MSCs) improve medication-related osteonecrosis of the jaw (MRONJ), and paracrine effects of secretomes from MSCs have been hypothesized as the primary contributors. These secretomes in conditioned media from human MSCs (MSC-CM) were previously demonstrated to promote bone and tissue regeneration. Because MSC-CM contain cytokines monocyte chemoattractant protein (MCP)-1, insulin growth factor (IGF)-1, and vascular endothelial growth factor (VEGF) at relatively higher concentrations than other factors, these cytokines were considered as relevant active factors for tissue regeneration. By mixing the recombinant proteins of MCP-1, IGF-1, and VEGF, included at the same concentrations in MSC-CM, we prepared cytokine mixtures mimicking MSC-CM and then evaluated its therapeutic effects in a rat MRONJ model. In vitro, cytokine mixtures promoted osteogenic differentiation, migration, and proliferation of rat MSCs. In addition, these maintained osteoclastic function. In vivo, we used a rat MRONJ model to examine therapeutic effects of the cytokine mixtures through intravenous administration. In MSC-CM or cytokine mixture group, open alveolar sockets in 66% or 67% of the rats with MRONJ, respectively, healed with complete soft tissue coverage and socket bones, whereas in the other groups, the exposed necrotic bone with inflamed soft tissue remained. Histological analysis revealed new bone formation and the appearance of osteoclasts in MSC-CM or cytokine mixture group; however, osteoclasts were significantly reduced in the other groups. Thus, we concluded that intravenous administration of cytokine mixtures might be an effective therapeutic modality for treating patients with MRONJ.

Clinical Study of Bone Regeneration by Conditioned Medium From Mesenchymal Stem Cells After Maxillary Sinus Floor Elevation.

OBJECTIVE: This clinical study was undertaken to evaluate the safety of use of the secretome of bone marrow-derived mesenchymal stem cells (MSC-CM) for maxillary sinus floor elevation (SFE). MATERIALS AND METHODS: MSC-CM was prepared from conditioned medium from human bone marrow-derived MSCs. Six partially edentulous patients were enrolled in the study. MSC-CM was mixed with porous beta-tricalcium phosphate (ß-TCP) and implanted in 4 patients (experimental group), whereas only ß-TCP was implanted in the other 2 patients (control group). Six months after SFE, bone biopsies and histological assessments were performed. RESULTS: Bone formation was clinically confirmed in all cases. Although Hounsfield units in computed tomography images were not significantly different between the groups, histological analysis revealed a significant difference in newly formed bone area between the groups. In particular, bone volume in the center of the augmented area was significantly greater in the MSC-CM group. Newly formed bone consisted of lamellar bone in the MSC-CM group but woven bone in the ß-TCP group. CONCLUSION: The secretome of bone marrow-derived mesenchymal stem cells (MSC-CM) was used safely and has great osteogenic potential for regenerative medicine of bone.

Near-Infrared 1064 nm Laser Modulates Migratory Dendritic Cells To Augment the Immune Response to Intradermal Influenza Vaccine.

Brief exposure of skin to near-infrared (NIR) laser light has been shown to augment the immune response to intradermal vaccination and thus act as an immunologic adjuvant. Although evidence indicates that the NIR laser adjuvant has the capacity to activate innate subsets including dendritic cells (DCs) in skin as conventional adjuvants do, the precise immunological mechanism by which the NIR laser adjuvant acts is largely unknown. In this study we sought to identify the cellular target of the NIR laser adjuvant by using an established mouse model of intradermal influenza vaccination and examining the alteration of responses resulting from genetic ablation of specific DC populations. We found that a continuous wave (CW) NIR laser adjuvant broadly modulates migratory DC (migDC) populations, specifically increasing and activating the Lang+ and CD11b-Lang- subsets in skin, and that the Ab responses augmented by the CW NIR laser are dependent on DC subsets expressing CCR2 and Langerin. In comparison, a pulsed wave NIR laser adjuvant showed limited effects on the migDC subsets. Our vaccination study demonstrated that the efficacy of the CW NIR laser is significantly better than that of the pulsed wave laser, indicating that the CW NIR laser offers a desirable immunostimulatory microenvironment for migDCs. These results demonstrate the unique ability of the NIR laser adjuvant to selectively target specific migDC populations in skin depending on its parameters, and highlight the importance of optimization of laser parameters for desirable immune protection induced by an NIR laser-adjuvanted vaccine.