The efficacy of mesenchymal stem cells in regenerating structures associated with the temporomandibular joint: A systematic review

Efficacy of IFN-γ-Primed Umbilical Cord-Derived Mesenchymal Stem Cells on Temporomandibular Joint Osteoarthritis

BACKGROUND

Temporomandibular joint osteoarthritis (TMJOA) is a degenerative disease affecting the cartilage and subchondral bone, leading to temporomandibular joint pain and dysfunction. The complex nature of TMJOA warrants effective alternative treatments, and mesenchymal stem cells (MSCs) have shown promise in regenerative therapies. The aim of this study is twofold: firstly, to ascertain the optimal interferon-gamma (IFN-γ)-primed MSC cell line for TMJOA treatment, and secondly, to comprehensively evaluate the therapeutic efficacy of IFN-γ-primed mesenchymal stem cells derived from the human umbilical cord matrix in a rat model of TMJOA.

METHODS

We analyzed changes in the expression of several key genes associated with OA protection in MSC-secreted compounds. Following this, we performed co-culture experiments using a transwell system to predict gene expression changes in primed MSCs in the TMJOA environment. Subsequently, we investigated the efficacy of the selected IFN-γ-primed human umbilical cord matrix-derived MSCs (hUCM-MSCs) for TMJOA treatment in a rat model.

RESULTS

IFN-γ-primed MSCs exhibited enhanced expression of IDO, TSG-6, and FGF-2. Moreover, co-culturing with rat OA chondrocytes induced a decrease in pro-inflammatory and extracellular matrix degradation factors. In the rat TMJOA model, IFN-γ-primed MSCs with elevated IDO1, TSG-6, and FGF2 expression exhibited robust anti-inflammatory and therapeutic capacities, promoting the improvement of the inflammatory environment and cartilage regeneration.

CONCLUSION

These findings underscore the importance of prioritizing the mitigation of the inflammatory milieu in TMJOA treatment and highlight IFN-γ-primed MSCs secreting these three factors as a promising, comprehensive therapeutic strategy.

Injectable Platelet-Rich Fibrin (I-PRF) Administered to Temporomandibular Joint Cavities: A Scoping Review

The aim of this review was to systematically map the research on the intra-articular administration of injectable platelet-rich fibrin (I-PRF) to the temporomandibular joints (TMJs). Medical databases covered by the ACM, BASE, Google, NLM, and ResearchGate were searched on 23 February 2023. The assessment of the level of evidence was based on the Oxford Center for Evidence-Based Medicine 2011 scale. The risk of bias was assessed for randomized controlled trials with the RoB2 tool. Extracted data were tabulated, and the changes in effect values were calculated. A total of eight studies qualified, of which five trials on 213 patients were randomized and controlled (RCTs). In each of the RTC study groups, arthrocentesis was performed, and 1-2 mL per joint of I-PRF (700 rpm/3 min/60 g centrifugation) was administered. Articular pain in three months decreased to 0-25% of the initial pre-interventional values in the study and 38-50% in the control groups. Mandible mobility increased to 121-153% and 115-120% in the I-PRF groups and controls, respectively. The main limitations of the evidence were the small number of RCTs and the lack of any RCT study groups receiving I-PRF without prior arthrocentesis. In conclusion, supplementing the temporomandibular joint rinsing with I-PRF administration further relieves pain and improves mandible mobility. The lack of RCTs on the intra-articular administration of I-PRF as a stand-alone procedure encourages further research. This research received no external funding. The review protocol has not been previously published.

Global Trends and Future Research Directions for Temporomandibular Disorders and Stem Cells

Temporomandibular disorder (TMD) is an umbrella term used to describe various conditions that affect temporomandibular joints, masticatory muscles, and associated structures. Although the most conservative and least invasive treatment is preferable, more invasive therapies should be employed to refractory patients. Tissue engineering has been presented as a promising therapy. Our study aimed to investigate trends and point out future research directions on TMD and stem cells. A comprehensive search was carried out in the Web of Science Core Collection (WoS-CC) in October 2022. The bibliometric parameters were analyzed through descriptive statistics and graphical mapping. Thus, 125 papers, published between 1992 and 2022 in 65 journals, were selected. The period with the highest number of publications and citations was between 2012 and 2022. China has produced the most publications on the subject. The most frequently used keywords were "cartilage", "temporomandibular joint", "mesenchymal stem cells", and "osteoarthritis". Moreover, the primary type of study was in vivo. It was noticed that using stem cells to improve temporomandibular joint repair and regeneration is a significant subject of investigation. Nonetheless, a greater understanding of the biological interaction and the benefits of using these cells in patients with TMD is required.

Annual review of selected scientific literature: A report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry

The Scientific Investigation Committee of the American Academy of Restorative Dentistry offers this review of the 2021 dental literature in restorative dentistry to inform busy dentists regarding noteworthy scientific and clinical progress over the past year. Each member of the committee brings discipline-specific expertise to coverage of this broad topical area. Specific subject areas addressed, in order of the appearance in this report, include COVID-19 and the dental profession (new); prosthodontics; periodontics, alveolar bone, and peri-implant tissues; implant dentistry; dental materials and therapeutics; occlusion and temporomandibular disorders; sleep-related breathing disorders; oral medicine and oral and maxillofacial surgery; and dental caries and cariology. The authors focused their efforts on reporting information likely to influence daily dental treatment decisions with an emphasis on future trends in dentistry. With the tremendous volume of dentistry and related literature being published daily, this review cannot possibly be comprehensive. Rather, its purpose is to update interested readers and provide important resource material for those interested in pursuing greater details on their own. It remains our intent to assist colleagues in negotiating the extensive volume of important information being published annually. It is our hope that readers find this work useful in successfully managing the patients and dental problems they encounter.

Autologous Stem Cells Transplants in the Treatment of Temporomandibular Joints Disorders: A Systematic Review and Meta-Analysis of Clinical Trials

This systematic review aims to analyze the outcomes of the treatment of temporomandibular joint (TMJ) articular pain (AP) and restricted maximum mouth opening (MMO) with intra-articular administration of mesenchymal stem cells (MSCs). The inclusion criteria allowed primary studies involving AP and/or MMO pre-treatment and post-intervention values. Medical databases that were covered by ACM Digital, BASE, EBSCOhost, Google Scholar, PubMed, Scopus, and Web of Science engines were searched. The risk of bias was assessed with RoB 2 and ROBINS-I tools. The results were tabulated, plotted, and analyzed for regression. A total of 5 studies involving 51 patients/69 TMJs were identified, and 4 studies on 50 patients/67 TMJs were synthesized. Interventions were each time effective in decreasing AP and increasing MMO in a 6-month follow-up period by an average of about 85% and over 40%, respectively. Regression analysis showed a good fit of the logarithmic model for AP relief (5.8 − 0.8 ln x; R² = 0.90) and MMO increase (33.5 + 2.4 ln x; R² = 0.89). The results for AP and MMO were based on 3 studies in 39 patients and 4 studies in 50 patients, respectively, all at high risk of bias. The intra-articular administration of MSCs to TMJs, based on weak evidence, may be highly effective in reducing AP and improving MMO. This study received no funding.