Osteoclasts in Osteosarcoma: Mechanisms, Interactions, and Therapeutic Prospects.

Osteosarcoma is an extremely malignant tumor, and its pathogenesis is complex and remains incompletely understood. Most cases of osteosarcoma are accompanied by symptoms of bone loss or result in pathological fractures due to weakened bones. Enhancing the survival rate of osteosarcoma patients has proven to be a long-standing challenge. Numerous studies mentioned in this paper, including in-vitro, in-vivo, and in-situ studies have consistently indicated a close association between the symptoms of bone loss associated with osteosarcoma and the presence of osteoclasts. As the sole cells capable of bone resorption, osteoclasts participate in a malignant cycle within the osteosarcoma microenvironment. These cells interact with osteoblasts and osteosarcoma cells, secreting various factors that further influence these cells, disrupting bone homeostasis, and shifting the balance toward bone resorption, thereby promoting the onset and progression of osteosarcoma. Moreover, the interaction between osteoclasts and various other cells types, such as tumor-associated macrophages, myeloid-derived suppressor cells, DCs cells, T cells, and tumor-associated fibroblasts in the osteosarcoma microenvironment plays a crucial role in disease progression. Consequently, understanding the role of osteoclasts in osteosarcoma has sparked significant interest. This review primarily examines the physiological characteristics and functional mechanisms of osteoclasts in osteosarcoma, and briefly discusses potential therapies targeting osteoclasts for osteosarcoma treatment. These studies provide fresh ideas and directions for future research on the treatment of osteosarcoma.

[Effect of different kinds of gingival retraction agents on the polymerization inhibition of polyvinyl siloxane impression materials].

PURPOSE: To evaluate the effect of different kinds of gingival retraction agents after directly contacted with polyvinyl siloxane impression materials on polymerization inhibition and the inhibition degree. METHODS: Five kinds of gingival retraction agents (0.1% epinephrine hydrochloride, 0.05% oxymetazoline, 15.5% ferric sulfate, 25% aluminum chloride and 5% aluminum chloride) were chosen, normal saline was as control group, and two kinds of polyvinyl siloxane impression materials (ExpressTM, ImprintTM Ⅱ) were combined into 12 groups. There were 12 specimens in each group and 144 specimens in total. Silicone rubber impression materials were mixed by the same operator using a dispensing gun into the acrylic mold, so that they could directly contact the gingival retraction agents on the densely woven cotton fabrics. The samples were removed when the polymerization time arrived according to the manufactures' recommendations and then placed under a stereomicroscope with a magnification of 10 times to observe whether polymerization inhibition occurred, the degree of inhibition was compared afterwards. SPSS 22.0 software package was used for statistical analysis. RESULTS: The polymerization inhibition of two kinds of silicone rubber impression materials occurred in 15.5% ferric sulfate group and 25% aluminum chloride group, and the inhibition occurrence rate was 100%, the difference was statistically significant (P＜0.05) compared with normal saline group. Inhibition was not found in 0.1% epinephrine hydrochloride group, 0.05% oxymetazoline group and 5% aluminum chloride. The effect of 15.5% ferric sulfate and 25% aluminum chloride on polymerization inhibition degree of ImprintTM Ⅱ was greater than ExpressTM, and the difference was statistically significant(P＜0.05). CONCLUSIONS: When silicone rubber impression material is used during impression procedure, attention should be paid to the effect of the gingival retraction agent containing 15.5% ferric sulfate and 25% aluminum chloride on its polymerization. The gingival retraction agent should be washed before impression to avoid the residue directly contacting the silicone rubber to prevent polymerization.

Photo-Responsive Hydrogel for Contactless Dressing Change to Attenuate Secondary Damage and Promote Diabetic Wound Healing.

Dressing change is a significant and inevitable process during wound healing. Possible secondary damage caused through dressing removal may impose a great threat on wound recovery, thus resulting in healing delays and ultimately a higher cost of hospitalization. Hence, a non-contact refreshable dressing with an ease of operation is of great desire, especially for chronic wounds where a long-term and repeated dressing change would be performed. Herein, an all-light-operated hydrogel dressing that would achieve a fast and remote-controllable dressing change (30 s for gelation/4 min for dissolution upon light irradiation) for chronic wounds is presented. In a diabetic murine model, substantially improved wound healing within 2-3 weeks is observed due to attenuated secondary damage during repeated dressing changes. Moreover, a promising facilitation of the healing processes of epithelialization, collagen deposition, cell proliferation, and inflammatory regulation is also detected, representing a synergistic effect of the photo-responsive hydrogel dressing for therapeutic efficiency.

One-Pot Synthesis of Bioadhesive Double-Network Hydrogel Patch as Disposable Wound Dressing.

Inventions of materials to achieve biocompatibility, bioadhesion, and easy manufacturing are the urgent demand for promoting wound healing in clinical treatment. Hyaluronic acid (HA) is probably the ideal candidate for current dressing materials due to its well-known biocompatibility. However, the unavoidable problem for HA dressings is their inherent low adhesiveness to wounds, which severely impairs their treatment efficacy, especially during body movement. Here, we report a one-pot facile fabrication of hybrid double-network polydopamine-HA (PDA-HA) hydrogel with significantly enhanced adhesiveness compared to the HA hydrogel. Besides the easy manufacturing and promoted effectiveness, the PDA-HA hydrogel could be vacuum-dried to form a patch, further benefitting from the convenience for storage and distribution. When applied on the wound, the PDA-HA patch quickly rehydrated by absorbing exudate and stuck tightly to the wound. The applied PDA-HA patches keep the wounds covered for more than 7 days against strenuous exercise. Thus, mouse full-thickness wounds treated with the PDA-HA patches exhibited increased healing rates, where epithelization was finished within 14 days. Moreover, the hydrogel dressing exhibited promoting effects on vascularization and cell proliferation/migration. Together with the easy manufacturing procedure, good adhesion/adaptation, and promotion of wound healing, the PDA-HA patch holds great potential for future clinical translation.

Dedifferentiated Schwann cell-derived TGF-ß3 is essential for the neural system to promote wound healing.

Rationale: Wound healing is among the most complicated physiological processes and requires the synchronization of various cell types with distinct roles to re-establish the condition of the original skin. Patients affected by peripheral neuropathies often experience failure to heal. Loss of Schwann cells (SCs), a crucial population of peripheral nervous system cells in skin, may contribute to chronic wounds. However, the role of SCs in wound healing are poorly understood. Methods: The activity of SCs was investigated by using a cell atlas of the wound healing process, which was generated by integrating single-cell RNA sequencing (scRNA-seq) libraries covering different states of mouse back skin. The results of in silico analysis were validated by in vitro cell culture and in vivo mouse model. Selective inhibitors and conditional RNAi by virus transfection were utilized to investigate the role of SCs in wound healing. Findings from mouse experiments were further verified in scRNA-seq analysis of diabetic patients. Results: Our in silico analysis revealed the heterogeneous cellular components of skin and the dynamic interactions of neural crest derived cells (NCs) with other cell types. We found that SCs dedifferentiated at an early stage of wound repair with upregulated Wnt signaling. We also identified dedifferentiated SC (dSC) defect in diabetic wounds in both mouse and human. Wnt inhibition at the wound site repressed SC dedifferentiation, leading to defective repair. Furthermore, dSCs derived TGF-ß3, which is context-dependent, promoted the migration of fibroblasts and keratinocytes. Moreover, TGF-ß3 supplementation enhanced the healing of chronic wounds in diabetic mice with impaired SCs. Conclusion: Our study thus advances the understanding of the roles of neural-derived cells in skin regeneration and suggests a potential therapeutic strategy for wound healing disorders.

The effect of glycerol as a cryoprotective agent in the cryopreservation of adipose tissue.

BACKGROUND: Long-term preservation of adipose tissue is crucial for clinical applications. Researchers should consider both efficiency and biosafety when choosing a cryoprotective agent (CPA) for adipose tissue preservation. Glycerol has been applied as a nontoxic CPA for multiple tissues but not adipose tissue. We aimed to evaluate the efficacy of glycerol as a CPA for adipose tissue cryopreservation. METHODS: Fresh human adipose tissues were obtained from patients who underwent liposuction and divided into 1 mL samples. Each sample was randomly mixed with 1 mL of CPA: 60-100% glycerol, 0.25 mol/L trehalose or DMSO + FBS and cryopreserved in - 196 °C liquid nitrogen for one month. After thawing and elution, the tissues were immediately evaluated for activity and structural integrity in vitro. Then, 0.2 mL of each sample was transplanted subdermally to the nude mouse dorsum and harvested after one month for histological examination to assess the effect of the cryopreserved fat in transplantation. RESULTS: After cryopreservation, the samples treated with DMSO + FBS, trehalose, 60% and 70% glycerol had a more integrated structure than the samples in other groups. Tissues preserved with 70% glycerol had the highest G3PDH activity of 24.41 ± 0.70, comparable to 24.76 ± 0.48 in fresh tissue (p > 0.05). Adipose-derived stem cells (ASC) viability, proliferation and differentiation capability were also better preserved in 70% glycerol group. In vivo analysis showed that tissue preserved with 70% glycerol had a retention rate of 52.37 ± 7.53%, significantly higher than other groups. Histological observation demonstrated better structural integrity and viability in 70% glycerol group. Compared to the DMSO + FBS and trehalose groups, the glycerol groups showed lower tissue inflammation. CONCLUSION: Glycerol (70%) is efficient in adipose tissue cryopreservation. Glycerol-based CPAs, which are nontoxic and show biosafety, are a promising solution for clinical tissue cryopreservation.

Mechanical Stretching Can Modify the Papillary Dermis Pattern and Papillary Fibroblast Characteristics during Skin Regeneration.

Clinical application of mechanical stretching is a reconstructive method for skin repair. Although studies have reported dermal fibroblast heterogeneity, whether stretching affects individual fibroblast subpopulations equally remains unclear. In this study, we show the changes in dermal structure and papillary fibroblast (Fp) in regenerated human skin. Exhausted skin regeneration caused dermal‒epidermal junction flattening, papillary dermis thinning, and an increase in type III collagen-to-type I collagen ratio, with upregulated hallmarks of aging. Well-regenerated skin displayed a notable increase in the Fp population. Consistent changes were observed in the rat expansion model. Moreover, we found that TGFß1 expression was especially increased in skin showing good regeneration. Activation of the TGFß1/SMAD2/3 pathway improved exhausted skin regeneration and resulted in increased collagen content and Fp proliferation, whereas pharmacological inhibition of TGFß1 action impacted well-regenerated skin. Short-term mechanical stretching that promoted skin regeneration enhanced Fp proliferation, extracellular matrix synthesis, and increased TGFß1 expression, leading to good regeneration. Conversely, long-term stretching induced premature Fp senescence, leading to poor regeneration. This work shows the mechanism of mechanical stretching in well-skin regeneration that enhances Fp proliferation and extracellular matrix synthesis through the TGFß1/SMAD2/3 pathway and highlights a crucial role of Fps in stretching-induced skin regeneration.

Autologous Concentrated Growth Factors Combined with Topical Minoxidil for the Treatment of Male Androgenetic Alopecia: A Randomized Controlled Clinical Trial.

Background: Minoxidil (MXD) is an U.S. Food and Drug Administration-approved drug for the topical treatment of androgenetic alopecia (AGA) with minor side effects, but its hair growth (HG) effect is unsatisfactory. Methods: A double-blinded within-subjects randomized clinical trial was conducted on 16 male AGA patients who showed limited improvement after MXD treatment. Eligible participants received three concentrated growth factor (CGF) injections on half of the scalp and the placebo on the other side at 4-week intervals, and MXD was applied twice daily on both sides throughout the follow-up period. The primary endpoint was the HG ratio at V4. The secondary endpoints included the HG ratios at V2, V3, and V5; hair density and T/V ratio at V2, V3, V4, and V5; Global Aesthetic Improvement Scale (GAIS) scores at V4 and V5; and participant satisfaction at V4. Results: Each group included 16 subjects; each half of the scalp was randomly assigned to the MXD+CGF or MXD group. The HG ratio at V4 was higher in the MXD+CGF group than in the MXD group. The MXD+CGF group had significant improvements in hair density, HG ratio, and T/V ratio compared with the MXD group over the follow-up period. The GAIS scores and participant satisfaction were higher in the MXD+CGF group than in the MXD group. Unexpectedly, the MXD+CGF treatment hastened HG, which was sustained for 3 months after discontinuation. No severe adverse events occurred. Conclusions: The combined treatment of MXD and CGF is safe and more efficient for AGA patients. Combining CGF can expedite the potency of MXD and provide patients with fast and lasting HG.

The combination of trehalose and glycerol: an effective and non-toxic recipe for cryopreservation of human adipose-derived stem cells.

BACKGROUND: Adipose-derived stem cells (ADSCs) promote tissue regeneration and repair. Cryoprotective agents (CPAs) protect cells from cryodamage during cryopreservation. Safe and efficient cryopreservation of ADSCs is critical for cell-based therapy in clinical applications. However, most CPAs are used at toxic concentrations, limiting their clinical application. OBJECTIVE: The aim of this study is to develop a non-toxic xeno-free novel CPA aiming at achieving high-efficiency and low-risk ADSC cryopreservation. METHODS: We explored different concentrations of trehalose (0.3 M, 0.6 M, 1.0 M, and 1.25 M) and glycerol (10%, 20%, and 30% v/v) for optimization and evaluated and compared the outcomes of ADSCs cryopreservation between a combination of trehalose and glycerol and the commonly used CPA DMSO (10%) + FBS (90%). All samples were slowly frozen and stored in liquid nitrogen for 30 days. The effectiveness was evaluated by the viability, proliferation, migration, and multi-potential differentiation of the ADSCs after thawing. RESULTS: Compared with the groups treated with individual reagents, the 1.0 M trehalose (Tre) + 20% glycerol (Gly) group showed significantly higher efficiency in preserving ADSC activities after thawing, with better outcomes in both cell viability and proliferation capacity. Compared with the 10% DMSO + 90% FBS treatment, the ADSCs preserved in 1.0 M Tre + 20% Gly showed similar cell viability, surface markers, and multi-potential differentiation but a significantly higher migration capability. The results indicated that cell function preservation can be improved by 1.0 M Tre + 20% Gly. CONCLUSIONS: The 1.0 M Tre + 20% Gly treatment preserved ADSCs with a higher migration capability than 10% DMSO + 90% FBS and with viability higher than that with trehalose or glycerol alone but similar to that with 10% DMSO + 90% FBS and fresh cells. Moreover, the new CPA achieves stemness and multi-potential differentiation similar to those in fresh cells. Our results demonstrate that 1.0 M Tre + 20% Gly can more efficiently cryopreserve ADSCs and is a non-toxic CPA that may be suitable for clinical applications.

Quantitative Proteomic Analysis of Rat Condylar Chondrocytes during Postnatal Development.

OBJECTIVE: To investigate differentially expressed proteins in rat mandibular condylar cartilage (MCC) chondrocytes caused by initial mastication for short postnatal periods. METHODS: Four groups of protein samples were extracted from primary cultured rat MCC chondrocytes, harvested from eigthy postnatal SD rats aged 1,7,14 and 28 days, with twenty in each group. Total proteins were labelled with isobaric tags for relative and absolute quantification (iTRAQ) reagents. Two-dimensional nano-high-performance liquid chromatography (HPLC) and matrix-assisted laser desorption ionization-time-of-flight/ time-of-flight (MALDI-TOF/TOF) mass spectrometry analysis with iTRAQ technique were performed. All data were analysed by MASCOT software with the SWISSPROT protein database. Furthermore, bioinformatics and statistical analysis were performed to classify their cellular components, biological processes, molecular functions and metabolic pathway by the PANTHER database. RESULTS: In total, 137 differentially expressed proteins were identified during MCC growth and were assigned to one or more cellular components. According to the PANTHER analysis, a significant proportion of proteins are involved in the metabolic process, cellular process, biological regulation, developmental process and response to stimulus. The most extensive molecular function was 43% in catalytic activity. In addition, it was found that proteins in MCC chondrocytes change markedly on the growth stage of eruption of the teeth. CONCLUSION: This study provides an integrated perspective of molecular mechanisms regulating early normal postnatal growth and development of rat MCC at the protein level.

[Correlation between platelet aggregation rates of aspirin users and intra-socket clotting after extraction of a maxillary tooth with periodontitis].

PURPOSE: To explore the optimal platelet aggregation rates (PAgTs) of aspirin users, which can ensure normal intra-socket clotting after extraction of a maxillary tooth with serious periodontitis, and to determine the reasonable time of pre-extraction aspirin suspension. METHODS: Ninety aspirin users (100mg/d) requiring extraction of a maxillary tooth with serious periodontitis were enrolled and divided into anterior tooth group (group A), premolar group (group B) and molar group (group C). Each group contained 10 cases with aspirin continuation, 10 cases with aspirin withdrawal 3 days pre-extraction and 10 cases with 5-day of aspirin withdrawal. After preoperative light transmission aggregometry (LTA) using arachidonic acid (AA) as the inducer to each case, the extractions were preformed. According to the intra-socket clotting classification table (class I indicated normal clotting, class II-III indicated successively increasing bleeding amount), the evaluation for each case was implemented and the analysis of the impacts caused by pre-extraction aspirin continuation and suspension on intra-socket clotting was conducted. The research on the best cut-off value of AA-induced PAgT to predict normal post-extraction clotting was also carried out by using receiver operating characteristic curve (ROC curve, SPSS11.6). RESULTS: (1)There were 4 cases of Class II in group A (3 without aspirin cessation and 1 with 3-day suspension), 8 in group B (5 without aspirin cessation, 2 with 3-day suspension and 1 with 5-day suspension) and 11 in group C (6 without aspirin cessation, 4 with 3-day suspension and 1 with 5-day suspension). The other cases in 3 groups were Class I. (2) The best cut-off value of AA induced PAgT was 10.15%, 13.25%, 16.5% for group A, B, C, respectively. CONCLUSIONS: For aspirin users (100mg/d) who will accept extraction of a maxillary tooth with serious periodontitis, a detection of pre-extraction LTA-AA is profitable, AA induced PAgT≥10.15% for an anterior tooth extraction, PAgT≥13.25% for a premolar extraction and PAgT≥16.5% for a molar extraction indicate normal postoperative intra-socket clotting, so aspirin continuation is feasible under such conditions. Otherwise, post-extraction bleeding amount can increase and preoperative aspirin cessation should be considered. The reasonable time of aspirin suspension is 3 days for an anterior tooth extraction and 5 days for a premolar or molar extraction. Additionally, hemostatic measures on the surgical site should be strengthened.

Influence of fiber posts on the fracture resistance of endodontically treated premolars with different dental defects.

This study aimed to evaluate the influence of quartz fiber post placement on the fracture resistance of endodontically treated premolars with different dental defects under dynamic loading. Fifty extracted single-rooted mandibular premolars were randomized into five groups. Each group was prepared according to numbers of residual walls ranged from 0 to 4. Then each group was divided into two subgroups with one restored with quartz fiber posts and the other without posts. In no-post groups, gutta percha point 2 mm below cemento-enamel junction was removed. Composite resin was adapted to the well and used to shape the core directly. Each tooth was restored with a complete metal crown. Dynamic loading was carried out in a masticatory simulator with a nominal load of 50 N at 2 Hz for 300 000 loading cycles. Then a quasi-statically load was applied in a universal testing machine 30° to the long axis with a crosshead speed of 1 mm⋅min(-1) until fracture. Data were analyzed with one-way analysis of variance and pairwise comparison (P<0.05). No specimens failed during dynamic loading. The fracture resistance enhanced with the increase of numbers of coronal walls and the differences were significant (P<0.05). Placement of fiber posts had a significant effect when fewer than two walls remained (P<0.05), but it had no significant influence in groups with two, three or four walls (P>0.05). Fiber post did not change failure mode, and the fracture pattern was mainly favorable. More dentin walls need to be retained in clinic. When no less than two walls remained, a fiber post is not always necessary.

[A clinical study on the stability of miniscrew anchorage in orthodontics].

PURPOSE: The aim of this retrospective study was to summarize the cases who used miniscrew anchorage and to evaluate the clinical factors influencing the stability of miniscrew. METHODS: The sample comprised 13 patients with 32 miniscrews, in whom the design, occlusogingival position, alveolar position, loading opportunity, gingival condition were investigated to assess the factors related to stability. The data was analyzed by univariate analysis and multivariate analysis using SAS 10.0 software package. RESULTS: The overall success rate was 90.6%. There was significant relationship between the patients' age and the stability of miniscrews (P=0.04). The success rate was 75% in adolescent patients, and 100% in adult patients. The osseointegration was affected by initial over-loading, but the long-term orthodontic loading (200g) was safe, if osseointegration was achieved. Perio-implant gingivitis, even the suppurative gingivitis (2 cases) didn't destroy the bone-implant interface. The success rate was independent on gender, occlusogingival position, jaw positioning, inserting times of the same miniscrew, and early loading. CONCLUSIONS: The primary stability is the crucial factor for long-term stability of the miniscrews.

[A study on the stability of miniscrew on different loading time as orthodontic anchorage].

PURPOSE: To evaluate the stability of the miniscrew on different loading time as orthodontic anchorage. METHODS: 2 healthy adult male Beagle dogs were used in this study. 48 mini-implants were implanted into the maxilla and mandible of the dogs. The miniscrews were divided into 8 different groups,1 group was loaded 0g as control group and the others were loaded 200g forces as experimental groups. 200g forces were loaded on the corresponding mini-implant anchorages immediately after implantation and at the time of 1w,2w,3w,4w,5w and 6w after implantation. The dogs were sacrificed at 12w after implantation. Histological progresses of implant-bone interfaces was examined with light microscope. Blue deposition and contact ratio were calculated and analyzed using SPSS13.0 software package. RESULTS: Fibrous and osseous-integration was noted in the interface, there was no significant difference in bone deposition ratio and bone contact ratio. CONCLUSION: Different force loading time does not affect the stability of the mini-implant anchorage.

[Progress of histological study on anchorage implants].

The study and the application of anchorage implants had attracted more and more attention from the orthodontists. This article reviewed the histological studies involving the implants used as orthodontic anchorage and found tendency to be micro-implants and self-drilling. The new concepts of osseointegration between micro-implant and bone, immediate loading, long-term loading and periodontal repair after injury from anchorage implant evoked challenges to the conventional understanding.