Mesenchymal Stem Cell Therapy for Osteoradionecrosis of the Mandible: a Systematic Review of Preclinical and Human Studies

Managing Mandibular Osteoradionecrosis

OBJECTIVE

Mandibular osteoradionecrosis (MORN) is a morbid complication of head and neck radiation therapy. Recent advances in surgical and medical therapies underscore the need for a shift in traditional treatment paradigms and a disease grading system that can guide appropriate management.

DATA SOURCES

Pubmed/MEDLINE.

REVIEW METHODS

We conducted a detailed review of publications related to MORN, specifically focusing on its staging and management techniques. Articles meeting inclusion criteria were synthesized into a final narrative review.

CONCLUSION

There has been a paradigm shift away from hyperbaric oxygen therapy in the management of MORN. Growing evidence for the efficacy of pentoxifylline and tocopherol in early-stage disease and novel surgical techniques to manage moderate and late-stage disease warrant an updated staging stratification which is proposed.

IMPLICATIONS FOR PRACTICE

This review summarizes the clinical efficacy of established and novel therapeutic modalities currently available in treating MORN, emphasizing the significant advances achieved over the last decade. It introduces a contemporary staging and treatment algorithm which incorporates traditional, evidence-supported surgical and medical management with effective early intervention strategies.

Application of Platelet-Rich Fibrin and Bone Morphogenetic Protein for Full-Mouth Implant-Based Oral Rehabilitation in a Case of Mandibular Osteoradionecrosis

Osteoradionecrosis (ORN) is a debilitating complication following radiation therapy, which in the head and neck region, occurs most frequently in the mandible. Although ORN is rare, it is complex and multifactorial and requires appropriate management. Manipulation of bone in patients with head and neck cancers before radiotherapy can cause ORN. In this report, we aim to present successful insertion of four dental implants in the interforaminal segment combined with application of platelet-rich fibrin and bone morphogenetic protein in a 60-year-old male with stable ORN in the posterior regions of the mandible.

The Use of Hydrogel-Based Materials for Radioprotection

Major causes of the radiation-induced disease include nuclear accidents, war-related nuclear explosions, and clinical radiotherapy. While certain radioprotective drug or bioactive compounds have been utilized to protect against radiation-induced damage in preclinical and clinical settings, these strategies are hampered by poor efficacy and limited utilization. Hydrogel-based materials are effective carriers capable of enhancing the bioavailability of compounds loaded therein. As they exhibit tunable performance and excellent biocompatibility, hydrogels represent promising tools for the design of novel radioprotective therapeutic strategies. This review provides an overview of common approaches to radioprotective hydrogel preparation, followed by a discussion of the pathogenesis of radiation-induced disease and the current states of research focused on using hydrogels to protect against these diseases. These findings ultimately provide a foundation for discussions of the challenges and future prospects associated with the use of radioprotective hydrogels.

Osseous Tissue Engineering in the Management of Mandibular Osteoradionecrosis - An Evaluative Study

Introduction

Osteoradionecrosis (ORN), a non-infectious, necrotic condition of the bone, occurs as a major complication of radiotherapy to the irradiated site. Simple irrigation of the involved bone to partial or complete resection of the involved bones is being employed in its conventional management. Osseous tissue engineering (OTE) provides a new strategy by regenerating bone cells along with biocompatible scaffolds and micromolecules to produce an engineered osseous tissue.

Materials and Methods

In this study, mandibular ORN following radiation secondary to oropharyngeal squamous cell carcinoma was included. OTE with composite engineered tissue containing a mixture of autologous culture expanded dental pulp stem cells (DPSCs), autologous uncultured bone marrow aspiration concentrate (BMAC) and autologous platelet-rich plasma (PRP) loaded in β-tricalcium phosphate (β-TCP) or hydroxyapatite (HA) sponge scaffold was used in the mandibular defect and the surrounding tissues. An assessment of clinical, radiological and functional attributes was done.

Results

A total of six cases with a mean age of 58.6 years were included in the study. We noted significant improvement in the mean post-operative score for pain and mouth opening; functional improvement in eating solid/liquid food, tongue movement, speech and deglutition were observed. The aesthetics was measured with Vancouver score and revealed a significance at P < 0.05; also lip competency and occlusion were noted in all the patients. No major complications were noticed until a mean follow-up of 28 months.

Discussion

Tissue engineering with a regenerative cocktail of autologous culture expanded DPSCs, autologous uncultured BMAC and autologous PRP loaded in HA or β-TCP utilised in the surgical reconstruction of the mandible is an effective treatment modality in the management of mandibular ORN following irradiation.

Human Mesenchymal Stromal Cells Do Not Cause Radioprotection of Head-and-Neck Squamous Cell Carcinoma

Radiotherapy of head-and-neck squamous cell carcinoma (HNSCC) can cause considerable normal tissue injuries, and mesenchymal stromal cells (MSCs) have been shown to aid regeneration of irradiation-damaged normal tissues. However, utilization of MSC-based treatments for HNSCC patients undergoing radiotherapy is hampered by concerns regarding potential radioprotective effects. We therefore investigated the influence of MSCs on the radiosensitivity of HNSCCs. Several human papillomavirus (HPV)-negative and HPV-positive HNSCCs were co-cultured with human bone marrow-derived MSCs using two-dimensional and three-dimensional assays. Clonogenic survival, proliferation, and viability of HNSCCs after radiotherapy were assessed depending on MSC co-culture. Flow cytometry analyses were conducted to examine the influence of MSCs on irradiation-induced cell cycle distribution and apoptosis induction in HNSCCs. Immunofluorescence stainings of γH2AX were conducted to determine the levels of residual irradiation-induced DNA double-strand breaks. Levels of connective tissue growth factor (CTGF), a multifunctional pro-tumorigenic cytokine, were analyzed using enzyme-linked immunosorbent assays. Neither direct MSC co-culture nor MSC-conditioned medium exerted radioprotective effects on HNSCCs as determined by clonogenic survival, proliferation, and viability assays. Consistently, three-dimensional microwell arrays revealed no radioprotective effects of MSCs. Irradiation resulted in a G2/M arrest of HNSCCs at 96 h independently of MSC co-culture. HNSCCs’ apoptosis rates were increased by irradiation irrespective of MSCs. Numbers of residual γH2AX foci after irradiation with 2 or 8 Gy were comparable between mono- and co-cultures. MSC mono-cultures and HNSCC-MSC co-cultures exhibited comparable CTGF levels. We did not detect radioprotective effects of human MSCs on HNSCCs. Our results suggest that the usage of MSC-based therapies for radiotherapy-related toxicities in HNSCC patients may be safe in the context of absent radioprotection.

Precursor structure-determined fluorescence labeling for mesenchymal stem cells among four polyethylenimine-based carbon quantum dots

A series of polyethylenimine (PEI)-based CQDs have been synthesized via a hydrothermal method by mixing linear PEI with linear citric acid (CA with COOH groups, PEICA), linear glucose (G with OH groups, PEIG), cyclic hyaluronic acid (HA with COOH groups, PEIHA) and cyclic boron nitride (BN with OH groups, PEIBN). PEICA had the best labeling effect (100.00 ± 0.26%) and the lowest cytotoxicity (100.89 ± 18.00%) for mesenchymal stem cells (MSCs), followed by PEIG (91.83 ± 7.60%; 92.84 ± 5.56%), PEIHA (84.34 ± 7.87%; 61.27 ± 11.34%) and PEIBN (1.33 ± 0.84%; 22.72 ± 11.47%). The labeling effect of PEIHA for MSCs is lower than that of PEIG because the surface potential of PEIHA (6.58 mV) is higher than that of PEIG (0.50 mV). For PEIBN, it is likely that the precursor (BN) is less biocompatible than CA, HA and glucose. Thus, the linear acid (CA) is more appropriate to react with PEI for synthesizing CQDs with high labeling performance for MSCs. The control experimental results show that factors (such as surface potential, aromatic component, etc.) may all contribute to MSC labeling by PEICA. This work is helpful to design CQDs with high MSC labeling efficiency.

Human mesenchymal stromal cells maintain their stem cell traits after high-LET particle irradiation - Potential implications for particle radiotherapy and manned space missions

The influence of high-linear energy transfer (LET) particle radiation on the functionalities of mesenchymal stromal cells (MSCs) is largely unknown. Here, we analyzed the effects of proton (¹H), helium (⁴He), carbon (¹²C) and oxygen (¹⁶O) ions on human bone marrow-MSCs. Cell cycle distribution and apoptosis induction were examined by flow cytometry, and DNA damage was quantified using γH2AX immunofluorescence and Western blots. Relative biological effectiveness values of MSCs amounted to 1.0-1.1 for ¹H, 1.7-2.3 for ⁴He, 2.9-3.4 for ¹²C and 2.6-3.3 for ¹⁶O. Particle radiation did not alter the MSCs' characteristic surface marker pattern, and MSCs maintained their multi-lineage differentiation capabilities. Apoptosis rates ranged low for all radiation modalities. At 24 h after irradiation, particle radiation-induced ATM and CHK2 phosphorylation as well as γH2AX foci numbers returned to baseline levels. The resistance of human MSCs to high-LET irradiation suggests that MSCs remain functional after exposure to moderate doses of particle radiation as seen in normal tissues after particle radiotherapy or during manned space flights. In the future, in vivo models focusing on long-term consequences of particle irradiation on the bone marrow niche and MSCs are needed.

Developing electropositive citric acid–polyethylenimine carbon quantum dots with high biocompatibility and labeling performance for mesenchymal stem cells in vitro and in vivo

The positive CQD has good biocompatibility (≤800 μg mL−1) and labelling performance for mesenchymal stem cell in vitro and in vivo.

The Particle Radiobiology of Multipotent Mesenchymal Stromal Cells: A Key to Mitigating Radiation-Induced Tissue Toxicities in Cancer Treatment and Beyond?

Mesenchymal stromal cells (MSCs) comprise a heterogeneous population of multipotent stromal cells that have gained attention for the treatment of irradiation-induced normal tissue toxicities due to their regenerative abilities. As the vast majority of studies focused on the effects of MSCs for photon irradiation-induced toxicities, little is known about the regenerative abilities of MSCs for particle irradiation-induced tissue damage or the effects of particle irradiation on the stem cell characteristics of MSCs themselves. MSC-based therapies may help treat particle irradiation-related tissue lesions in the context of cancer radiotherapy. As the number of clinical proton therapy centers is increasing, there is a need to decidedly investigate MSC-based treatments for particle irradiation-induced sequelae. Furthermore, therapies with MSCs or MSC-derived exosomes may also become a useful tool for manned space exploration or after radiation accidents and nuclear terrorism. However, such treatments require an in-depth knowledge about the effects of particle radiation on MSCs and the effects of MSCs on particle radiation-injured tissues. Here, the existing body of evidence regarding the particle radiobiology of MSCs as well as regarding MSC-based treatments for some typical particle irradiation-induced toxicities is presented and critically discussed.