Protective efficacy of intravenous transplantation of adipose-derived stem cells for the prevention of radiation-induced salivary gland damage

Role of Mesenchymal Stem/Stromal Cells in Head and Neck Cancer-Regulatory Mechanisms of Tumorigenic and Immune Activity, Chemotherapy Resistance, and Therapeutic Benefits of Stromal Cell-Based Pharmacological Strategies

Head and neck cancer (HNC) entails a heterogenous neoplastic disease that arises from the mucosal epithelium of the upper respiratory system and the gastrointestinal tract. It is characterized by high morbidity and mortality, being the eighth most common cancer worldwide. It is believed that the mesenchymal/stem stromal cells (MSCs) present in the tumour milieu play a key role in the modulation of tumour initiation, development and patient outcomes; they also influence the resistance to cisplatin-based chemotherapy, the gold standard for advanced HNC. MSCs are multipotent, heterogeneous and mobile cells. Although no MSC-specific markers exist, they can be recognized based on several others, such as CD73, CD90 and CD105, while lacking the presence of CD45, CD34, CD14 or CD11b, CD79α, or CD19 and HLA-DR antigens; they share phenotypic similarity with stromal cells and their capacity to differentiate into other cell types. In the tumour niche, MSC populations are characterized by cell quiescence, self-renewal capacity, low reactive oxygen species production and the acquisition of epithelial-to-mesenchymal transition properties. They may play a key role in the process of acquiring drug resistance and thus in treatment failure. The present narrative review examines the links between MSCs and HNC, as well as the different mechanisms involved in the development of resistance to current chemo-radiotherapies in HNC. It also examines the possibilities of pharmacological targeting of stemness-related chemoresistance in HNSCC. It describes promising new strategies to optimize chemoradiotherapy, with the potential to personalize patient treatment approaches, and highlights future therapeutic perspectives in HNC.

Mesenchymal Stromal/Stem Cell Therapy Improves Salivary Flow Rate in Radiation-Induced Salivary Gland Hypofunction in Preclinical in vivo Models: A Systematic Review and Meta-Analysis

BACKGROUND

Mesenchymal stromal/stem cells (MSCs) have been suggested for salivary gland (SG) restoration following radio-induced salivary gland damage. This study aimed to determine the safety and effectiveness of MSC therapy on radio-induced SG damage and hypofunction in preclinical in vivo studies.

METHODS

PubMed and EMBASE were systematically searched for preclinical in vivo interventional studies evaluating efficacy and safety of MSC treatment following radio-induced salivary gland damage published before 10th of January 2022. The primary endpoint was salivary flow rate (SFR) evaluated in a meta-analysis. The study protocol was published and registered on PROSPERO ( www.crd.ac.uk/prospero ), registration number CRD42021227336.

RESULTS

A total of 16 preclinical in vivo studies were included for qualitative analysis (858 experimental animals) and 13 in the meta-analysis (404 experimental animals). MSCs originated from bone marrow (four studies), adipose tissue (10 studies) and salivary gland tissue (two studies) and were administered intravenously (three studies), intra-glandularly (11 studies) or subcutaneously (one study). No serious adverse events were reported. The overall effect on SFR was significantly increased with a standardized mean difference (SMD) of 6.99 (95% CI: 2.55-11.42). Studies reported improvements in acinar tissue, vascular areas and paracrine factors.

CONCLUSION

In conclusion, this systematic review and meta-analysis showed a significant effect of MSC therapy for restoring SG functioning and regenerating SG tissue following radiotherapy in preclinical in vivo studies without serious adverse events. MSC therapy holds significant therapeutic potential in the treatment of radio-induced xerostomia, but comprehensive, randomized, clinical trials in humans are required to ascertain their efficacy in a clinical setting.

Reparative potential of mesenchymal stem cells and platelet-rich plasma on irradiated submandibular glands of male albino rats

OBJECTIVE

To appraise and compare the reparative role of bone marrow-mesenchymal stem cells (BM-MSCs) and platelet-rich plasma (PRP) against irradiation damage on albino rats' submandibular gland.

DESIGN

Seventy four male albino rats were used, one for BM-MSCs harvesting, 10 for PRP preparation, seven as control group (Group 1). The remaining 56 rats were subjected to single dose (6 Gy) gamma irradiation and were divided into equal four groups; (Group 2): received no treatment, (Group 3): each rat was injected with 1 × 10⁵ BM-MSCs, (Group 4): each rat was injected with 0.5 ml/kg PRP, and (Group 5): each rat was injected with 1 × 10⁵ BM-MSCs and 0.5 ml/kg PRP. Each group was further subdivided into two subgroups in which rats sacrificed after one and two weeks from irradiation. Any structural changes were examined histopathologically, immunohistochemically using proliferating cell nuclear antigen (PCNA) and CD31 primary antibodies and histochemically using picrosirius red (PSR) stain, then analyzed statistically.

RESULTS

Histopathological examination of Group 2 showed atrophied acini, with nuclear changes and signs of degeneration in duct systems. Treated groups revealed signs of regeneration in form of uniform acini and regenerated duct systems especially in Group 5 and in a time depended manner. Immunohistochemical examination revealed increased immunoexpression of PCNA and CD31, while histochemical examination showed decreased PSR in all treated groups in relation to the irradiated group and this was proved statistically.

CONCLUSIONS

BM-MSCs and PRP are effective as treatment for irradiation-induced submandibular gland damage. However, the combined therapy is recommended over each one separately.

Radiotherapy-Induced Digestive Injury: Diagnosis, Treatment and Mechanisms

Radiotherapy is one of the main therapeutic methods for treating cancer. The digestive system consists of the gastrointestinal tract and the accessory organs of digestion (the tongue, salivary glands, pancreas, liver and gallbladder). The digestive system is easily impaired during radiotherapy, especially in thoracic and abdominal radiotherapy. In this review, we introduce the physical classification, basic pathogenesis, clinical characteristics, predictive/diagnostic factors, and possible treatment targets of radiotherapy-induced digestive injury. Radiotherapy-induced digestive injury complies with the dose-volume effect and has a radiation-based organ correlation. Computed tomography (CT), MRI (magnetic resonance imaging), ultrasound (US) and endoscopy can help diagnose and evaluate the radiation-induced lesion level. The latest treatment approaches include improvement in radiotherapy (such as shielding, hydrogel spacers and dose distribution), stem cell transplantation and drug administration. Gut microbiota modulation may become a novel approach to relieving radiogenic gastrointestinal syndrome. Finally, we summarized the possible mechanisms involved in treatment, but they remain varied. Radionuclide-labeled targeting molecules (RLTMs) are promising for more precise radiotherapy. These advances contribute to our understanding of the assessment and treatment of radiation-induced digestive injury.

Labial Stem Cell Extract Mitigates Injury to Irradiated Salivary Glands

Stem cell-based therapies could provide a permanent treatment for salivary gland (SG) hypofunction caused by ionizing radiation (IR) injury. However, current challenges for SG stem cells to reach the clinic include surgical invasiveness, amount of tissue needed, cell delivery, and storage methods. The objective of this study was to develop a clinically less invasive method to isolate and expand human SG stem cells and then to obtain a cell-free extract to be used as a therapy for IR-injured SGs. Human labial glands were biopsied, and labial stem cells (LSCs) were expanded by explant culture. The LSC extract (LSCE) was obtained by releasing the cellular components after 3 freeze-thaw cycles and 17,000g force centrifugation. LSCE was injected intravenously into mice that had their SGs injured with 13-Gy IR. Positive (non-IR) and negative (IR) control mice received injections of saline (vehicle control). Three pieces of labial glands (0.1 g weight) could expand 1 to 2 million cells. LSCs had a doubling time of 18.8 h; could differentiate into osteocytes, adipocytes, and chondrocytes; and were positive for mesenchymal stem cell markers. Both angiogenic (FGF-1, FGF-2, KGF, angiopoietin, uPA, VEGF) and antiangiogenic factors (PAI-1, TIMP-1, TSP-1, CD26) were detected in LSCE. In addition, some angiogenic factors (PEDF, PTX3, VEGF) possessed neurotrophic functions. Mice treated with LSCE had 50% to 60% higher salivary flow rate than saline-treated mice at 8 and 12 wk post-IR. Saliva lag time measurements also confirmed that LSCE restored SG function. Histologic analyses of parotids and submandibular glands reported comparable numbers of acinar cells, blood vessels, and parasympathetic nerves and cell proliferation rates in sham IR and LSCE-treated mice, though significantly lower in saline-treated mice. An explant culture method can harvest a large number of LSCs from small pieces of labial glands. LSCE showed clinical potential to mitigate IR-injured SGs.

Adipose-derived mesenchymal stem cells regenerate radioiodine-induced salivary gland damage in a murine model

After radioiodine (RI) therapy, patients with thyroid cancer frequently suffer from painful salivary gland (SG) swelling, xerostomia, taste alterations, and oral infections. This study was aimed to determine whether adipose-derived mesenchymal stem cells (AdMSCs) might restore RI-induced SG dysfunction in a murine model. Forty -five mice were divided into three groups; a PBS sham group, a RI+ PBS sham group (0.01 mCi/g mouse, orally), and an RI+AdMSCs (1 × 10⁵ cells/150 uL, intraglandular injection on experimental day 28) treated group. At 16 weeks after RI treatment, body weights, SG weight, salivary flow rates (SFRs), and salivary lag times were measured. Morphologic and histologic examinations and immunohistochemistry (IHC) were performed and the activities of amylase and EGF in saliva were also measured. Changes in salivary ^99mTc pertechnetate excretion were followed by SPECT and TUNEL assays were performed. The body and SG weights were similar in the AdMSCs and sham groups. Hematoxylin and eosin staining revealed the AdMSCs group had more mucin-containing acini than the RI group. Furthermore, AdMSCs treatment resulted in tissue remodeling and elevated expressions of epithelial (AQP5) and endothelial (CD31) markers, and increased SFRs. The activities of amylase and EGF were higher in the AdMSCs group than in the RI treated group. ^99mTc pertechnetate excretions were similar in the AdMSCs and sham group. Also, TUNEL positive apoptotic cell numbers were less in the AdMSCs group than in the RI group. Local delivery of AdMSCs might regenerate SG damage induced by RI.

Stem cells from exfoliated deciduous teeth alleviate hyposalivation caused by Sjögren syndrome

OBJECTIVES

To evaluate the effect of stem cells  from  exfoliated  deciduous  teeth on the hyposalivation caused by Sjögren syndrome (SS) and investigate the mechanism.

METHODS

Stem cells were injected into the tail veins of non-obese diabetic mice, the animal model of SS. The saliva flow was measured after pilocarpine intraperitoneal injection. Apoptosis and autophagy were evaluated by TUNEL and Western blot. Lymphocyte proportions were detected by flow cytometer.

RESULTS

Fluid secretion was decreased in 21-week-old mice. Stem cell treatment increased fluid secretion, alleviated inflammation in the submandibular glands and reduced inflammatory cytokine levels in the serum, submandibular glands and saliva. Stem cells decreased the apoptotic cell number and the expressions of ATG5 and Beclin-1 in the submandibular glands. Stem cells have no effect on other organs. Furthermore, the infused stem cells migrated to the spleen and liver, not the submandibular gland. Stem cells directed T cells towards Treg cells and suppressed Th1 and Tfh cells in spleen lymphocytes.

CONCLUSION

Stem cells  from  exfoliated  deciduous  teeth alleviate the hyposalivation caused by SS via decreasing the inflammatory cytokines, regulating the inflammatory microenvironment and decreasing the apoptosis and autophagy. The stem cells regulated in T-cell differentiation are involved in the immunomodulatory effects.

Transplantation of Bone Marrow-Derived Mesenchymal Stem Cells Preserve the Salivary Glands Structure after Head and Neck Radiation in Rats

BACKGROUND

The salivary glands are one of the radiation sensitive tissues during radiotherapy in the treatment of head and neck cancer. Within the first weeks of radiotherapy, the radiation causes progressive loss of gland function, then continue throughout the later of the patient's life.

AIM

The present work was designed to discover the potential effect of bone marrow-derived mesenchymal stem cells (MSCs) injected locally and in decreasing the unwanted effects of radiation on rats salivary gland.

MATERIAL AND METHODS

6 rats used as the control group (N) and 12 rats had a single radiation dose of 13Gy in the head and neck then, they were equally allocated into two groups: Irradiated only as a group (C), Irradiated then treated with MSCs as a group (S). The animals were euthanised 7 days post radiation. Then, submandibular salivary glands were cut up; the histological examination was done.

RESULTS

Histological examination of the treated group(S) shown an apparent improvement in the SG structure and function compared to the irradiated group (C), this improvement represented mainly as preserving acini diameter (mean diameter in µm group (C) 183.1 ± 4.5, in group (S) 356.3 ± 33.5 while, in (N) group 408.9 ± 5.9) and decrease in fibrotic areas in the gland (mean fibrosis parentage in group (C) 26.5 ± 5.9 in (C) group , in group (S) 11.7 ± 4.13 while in (N) group 0.2 ± 0.31).

CONCLUSION

BM-MSCs has revealed to be promising in mitigating the side effects of radiotherapy on salivary glands structure.

Therapeutic effects of a recombinant human collagen peptide bioscaffold with human adipose-derived stem cells on impaired wound healing after radiotherapy

Chronic changes following radiotherapy include alterations in tissue-resident stem cells and vasculatures, which can lead to impaired wound healing. In this study, novel recombinant human collagen peptide (rhCP) scaffolds were evaluated as a biomaterial carrier for cellular regenerative therapy. Human adipose-derived stem cells (hASCs) were successfully cultured on rhCP scaffolds. By hASC culture on rhCP, microarray assay indicated that expression of genes related to cell proliferation and extracellular matrix production was upregulated. Pathway analyses revealed that signaling pathways related to inflammatory suppression and cell growth promotion were activated as well as signaling pathways consistent with some growth factors including vascular endothelial growth factor, hepatocyte growth factor, and transforming growth factor beta, although gene expression of these growth factors was not upregulated. These findings suggest the rhCP scaffold showed similar biological actions to cytokines regulating cell growth and immunity. In subsequent impaired wound healing experiments using a locally irradiated (20 Gray) mouse, wound treatment with rhCP sponges combined with cultured hASCs and human umbilical vein endothelial cells accelerated wound closure compared with wounds treated with rhCP with hASCs alone, rhCP only, and control (dressing alone), with better healing observed according to this order. These results indicating the therapeutic value of rhCP scaffolds as a topical biomaterial dressing and a biocarrier of stem cells and vascular endothelial cells for regenerating therapies. The combination of rhCP and functional cells was suggested to be a potential tool for revitalizing stem cell-depleted conditions such as radiation tissue damage.

Intraglandular transplantation of adipose-derived stem cells combined with platelet-rich fibrin extract for the treatment of irradiation-induced salivary gland damage

The aim of the present study was to determine the effect of adipose-derived mesenchymal stem cells (ADSCs) combined with heterologous platelet-rich fibrin extract (PRFe) on irradiation-induced salivary gland (SG) damage. ADSCs were isolated from C3H mice, whereas PRFe was obtained from New Zealand rabbits. Twelve weeks post irradiation, the ADSCs or PRFe or their combination were transplanted into the submandibular glands of C3H mice with irradiation-induced damage. The salivary flow rate (SFR) was determined and histopathological analysis was performed at 12 weeks post transplantation. Immunofluorescence, microvessel density measurements and transmission electron microscopy were performed to assess α-amylase (AMY) production, apoptosis and microstructural changes in the cells. The administration of ADSCs combined with PRFe increased the SFR at 12 weeks post transplantation, whereas ADSCs alone or PRFe alone failed to do so. The ADSCs+PRFe-treated, irradiated SGs had fewer damaged and atrophied acinar cells, higher AMY levels and an increased microvessel density compared with the untreated irradiated SGs. Moreover, SG tissue from the ADSCs+PRFe group also showed decreased apoptotic and increased proliferative activity compared to that from the irradiated group. In conclusion, ADSCs or PRFe alone did not restore permanent, irradiation-induced damage of SG tissue when used alone, but when used together, they provided effective treatment outcomes.

Treatment of late sequelae after radiotherapy for head and neck cancer

Radiotherapy (RT) is used to treat approximately 80% of patients with cancer of the head and neck. Despite enormous advances in RT planning and delivery, a significant number of patients will experience radiation-associated toxicities, especially those treated with concurrent systemic agents. Many effective management options are available for acute RT-associated toxicities, but treatment options are much more limited and of variable benefit among patients who develop late sequelae after RT. The adverse impact of developing late tissue damage in irradiated patients may range from bothersome symptoms that negatively affect their quality of life to severe life-threatening complications. In the region of the head and neck, among the most problematic late effects are impaired function of the salivary glands and swallowing apparatus. Other tissues and structures in the region may be at risk, depending mainly on the location of the irradiated tumor relative to the mandible and hearing apparatus. Here, we review the available evidence on the use of different therapeutic strategies to alleviate common late sequelae of RT in head and neck cancer patients, with a focus on the critical assessment of the treatment options for xerostomia, dysphagia, mandibular osteoradionecrosis, trismus, and hearing loss.

Adipose-derived stromal cell in regenerative medicine: A review

The application of appropriate cell origin for utilizing in regenerative medicine is the major issue. Various kinds of stem cells have been used for the tissue engineering and regenerative medicine. Such as, several stromal cells have been employed as treat option for regenerative medicine. For example, human bone marrow-derived stromal cells and adipose-derived stromal cells (ADSCs) are used in cell-based therapy. Data relating to the stem cell therapy and processes associated with ADSC has developed remarkably in the past 10 years. As medical options, both the stromal vascular and ADSC suggests good opportunity as marvelous cell-based therapeutics. The some biological features are the main factors that impact the regenerative activity of ADSCs, including the modulation of the cellular immune system properties and secretion of bioactive proteins such as cytokines, chemokines and growth factors, as well as their intrinsic anti-ulcer and anti-inflammatory potential. A variety of diseases have been treated by ADSCs, and it is not surprising that there has been great interest in the possibility that ADSCs might be used as therapeutic strategy to improve a wider range of diseases. This is especially important when it is remembered that routine therapeutic methods are not completely effective in treat of diseases. Here, it was discuss about applications of ADSC to colitis, liver failure, diabetes mellitus, multiple sclerosis, orthopaedic disorders, hair loss, fertility problems, and salivary gland damage.

Bone marrow mesenchymal stem cells attenuate 2,5-hexanedione-induced neuronal apoptosis through a NGF/AKT-dependent pathway

Growing evidence suggests that the increased neuronal apoptosis is involved in n-hexane-induced neuropathy. We have recently reported that bone marrow-mesenchymal stem cells-derived conditioned medium (BMSC-CM) attenuated 2,5-hexanedione (HD, the active metabolite of n-hexane)-induced apoptosis in PC12 cells. Here, we explored the anti-apoptotic efficacy of BMSC in vivo. HD-treated rats received BMSC by tail vein injection 5 weeks after HD intoxication. We found that in grafted rats, BMSC significantly attenuated HD-induced neuronal apoptosis in the spinal cord, which was associated with elevation of nerve growth factor (NGF). Neutralization of NGF in BMSC-CM blocked the protection against HD-induced apoptosis in VSC4.1 cells, suggesting that NGF is essential for BMSC-afforded anti-apoptosis. Mechanistically, we found that the decreased activation of Akt induced by HD was significantly recovered in the spinal cord by BMSC and in VSC4.1 cells by BMSC-CM in a TrkA-dependent manner, leading to dissociation of Bad/Bcl-xL complex in mitochondria and release of anti-apoptotic Bcl-xL. The importance of Akt was further corroborated by showing the reduced anti-apoptotic potency of BMSC in HD-intoxicated VSC4.1 cells in the presence of Akt inhibitor, MK-2206. Thus, our findings show that BMSC attenuated HD-induced neuronal apoptosis in vivo through a NGF/Akt-dependent manner, providing a novel solution against n-hexane-induced neurotoxicity.

Xerostomia: current streams of investigation

Xerostomia is the subjective feeling of dry mouth, and it is often related to salivary hypofunction. Besides medication-related salivary hypofunction, Sjögren syndrome and head-and-neck radiation are two common etiologies that have garnered considerable attention. Approaches to treating and/or preventing salivary hypofunction in patients with these conditions will likely incorporate gene therapy, stem cell therapy, and tissue engineering. Advances in these disciplines are central to current research in the cure for xerostomia and will be key to eventual treatment.