Regenerative capacity of allogenic gingival margin- derived stem cells with fibrin glue on albino rats' partially dissected submandibular salivary glands

Gingival-derived mesenchymal stem cell therapy regenerated the radiated salivary glands: functional and histological evidence in murine model

BACKGROUND

Radiotherapy in head and neck cancer management causes degeneration of the salivary glands (SG). This study was designed to determine the potential of gingival mesenchymal stem cells (GMSCs) as a cell-based therapy to regenerate irradiated parotid SG tissues and restore their function using a murine model.

METHODS

Cultured isolated cells from gingival tissues of 4 healthy guinea pigs at passage 3 were characterized as GMSCSs using flow cytometry for surface markers and multilineage differentiation capacity. Twenty-one Guinea pigs were equally divided into three groups: Group I/Test, received single local irradiation of 15 Gy to the head and neck field followed by intravenous injection of labeled GMSCs, Group II/Positive control, which received the same irradiation dose followed by injection of phosphate buffer solution (PBS), and Group III/Negative control, received (PBS) injection only. Body weight and salivary flow rate (SFR) were measured at baseline, 11 days, 8-, 13- and 16-weeks post-irradiation. At 16 weeks, parotid glands were harvested for assessment of gland weight and histological and immunohistochemical analysis.

RESULTS

The injected GMSCs homed to degenerated glands, with subsequent restoration of the normal gland histological acinar and tubular structure associated with a significant increase in cell proliferation and reduction in apoptotic activity. Subsequently, a significant increase in body weight and SFR, as well as an increase in gland weight at 16 weeks in comparison with the irradiated non-treated group were observed.

CONCLUSION

The study provided a new potential therapeutic strategy for the treatment of xerostomia by re-engineering radiated SG using GMSCs.

Stem cells and extracellular vesicles to improve preclinical orofacial soft tissue healing

Orofacial soft tissue wounds caused by surgery for congenital defects, trauma, or disease frequently occur leading to complications affecting patients' quality of life. Scarring and fibrosis prevent proper skin, mucosa and muscle regeneration during wound repair. This may hamper maxillofacial growth and speech development. To promote the regeneration of injured orofacial soft tissue and attenuate scarring and fibrosis, intraoral and extraoral stem cells have been studied for their properties of facilitating maintenance and repair processes. In addition, the administration of stem cell-derived extracellular vesicles (EVs) may prevent fibrosis and promote the regeneration of orofacial soft tissues. Applying stem cells and EVs to treat orofacial defects forms a challenging but promising strategy to optimize treatment. This review provides an overview of the putative pitfalls, promises and the future of stem cells and EV therapy, focused on orofacial soft tissue regeneration.

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.

Botanicals and Oral Stem Cell Mediated Regeneration: A Paradigm Shift from Artificial to Biological Replacement

Stem cells are a well-known autologous pluripotent cell source, having excellent potential to develop into specialized cells, such as brain, skin, and bone marrow cells. The oral cavity is reported to be a rich source of multiple types of oral stem cells, including the dental pulp, mucosal soft tissues, periodontal ligament, and apical papilla. Oral stem cells were useful for both the regeneration of soft tissue components in the dental pulp and mineralized structure regeneration, such as bone or dentin, and can be a viable substitute for traditionally used bone marrow stem cells. In recent years, several studies have reported that plant extracts or compounds promoted the proliferation, differentiation, and survival of different oral stem cells. This review is carried out by following the PRISMA guidelines and focusing mainly on the effects of bioactive compounds on oral stem cell-mediated dental, bone, and neural regeneration. It is observed that in recent years studies were mainly focused on the utilization of oral stem cell-mediated regeneration of bone or dental mesenchymal cells, however, the utility of bioactive compounds on oral stem cell-mediated regeneration requires additional assessment beyond in vitro and in vivo studies, and requires more randomized clinical trials and case studies.

Gingiva-Derived Mesenchymal Stem Cells: Potential Application in Tissue Engineering and Regenerative Medicine - A Comprehensive Review

A unique subpopulation of mesenchymal stem cells (MSCs) has been isolated and characterized from human gingival tissues (GMSCs). Similar to MSCs derived from other sources of tissues, e.g. bone marrow, adipose or umbilical cord, GMSCs also possess multipotent differentiation capacities and potent immunomodulatory effects on both innate and adaptive immune cells through the secretion of various types of bioactive factors with immunosuppressive and anti-inflammatory functions. Uniquely, GMSCs are highly proliferative and have the propensity to differentiate into neural cell lineages due to the neural crest-origin. These properties have endowed GMSCs with potent regenerative and therapeutic potentials in various preclinical models of human disorders, particularly, some inflammatory and autoimmune diseases, skin diseases, oral and maxillofacial disorders, and peripheral nerve injuries. All types of cells release extracellular vesicles (EVs), including exosomes, that play critical roles in cell-cell communication through their cargos containing a variety of bioactive molecules, such as proteins, nucleic acids, and lipids. Like EVs released by other sources of MSCs, GMSC-derived EVs have been shown to possess similar biological functions and therapeutic effects on several preclinical diseases models as GMSCs, thus representing a promising cell-free platform for regenerative therapy. Taken together, due to the easily accessibility and less morbidity of harvesting gingival tissues as well as the potent immunomodulatory and anti-inflammatory functions, GMSCs represent a unique source of MSCs of a neural crest-origin for potential application in tissue engineering and regenerative therapy.

Gingiva-derived Mesenchymal Stem Cells and Their Potential Applications in Oral and Maxillofacial Diseases

BACKGROUND

Stem cells are undifferentiated cells with multilineage differentiation potential. They can be collected from bone marrow, fat, amniotic fluid, and teeth. Stem cell-based therapies have been widely used to treat multiple diseases, such as cardiac disease, and hematological disorders. The cells may also be beneficial for controlling the disease course and promoting tissue regeneration in oral and maxillofacial diseases. Oral-derived gingival mesenchymal stem cells are easy to access and the donor sites heal rapidly without a scar. Such characteristics demonstrate the beneficial role of GMSCs in oral and maxillofacial diseases.

OBJECTIVE

We summarize the features of GMSCs, including their self-renewal, multipotent differentiation, immunomodulation, and anti-inflammation properties. We also discuss their applications in oral and maxillofacial disease treatment and tissue regeneration.

CONCLUSION

GMSCs are easily harvestable adult stem cells with outstanding proliferation, differentiation, and immunomodulation characteristics. A growing body of evidence indicates that GMSCs have strong potential use in accelerating wound healing and promoting the regeneration of bone defects, periodontium, oral neoplasms, salivary glands, peri-implantitis, and nerves. Moreover, alginate, polylactic acid and polycaprolactone can be used as biodegradable scaffolds for GMSC encapsulation. Various growth factors can be applied to the corresponding scaffolds to obtain the desired GMSC differentiation and phenotypes. Three-dimensional spheroid culture systems could optimize GMSC properties and improve the performance of the cells in tissue engineering. The immunomodulatory property of GMSCs in controlling oral and maxillofacial inflammation needs further research.

Effect of melatonin versus injectable platelet rich fibrin on critical wound healing in submandibular salivary glands of diabetic rats

Background

Diabetes mellitus (DM) has harmful effects on body organs, including submandibular salivary glands (SMGs). It impairs wound healing process that follow sialoadenectomy. Yet there is no complete cure to diabetes, the available medications tend to control the side effects of DM or manage insulin resistance. Herein we tried to investigate the possible effects of injectable platelet rich fibrin (i-PRF) and melatonin on wound healing in diabetic rats.

Material and methods

Surgical defects were created in SMGs of 30 rats after confirmation of DM induction. Then rats were randomly and equally allocated into three groups. Group I served as control group; group II received topically applied i-PRF, and group III received topically administrated melatonin. After 28 days all rats were euthanized, and SMGs were processed for histological and biochemical analysis.

Results

Both i-PRF and melatonin caused significant reduction of malondialdehyde (P < 0.0001) and caspase-3 (P < 0.001) and significant increase in vascular endothelial growth factors (P = 0.001,0.009 respectively) that increased SMGs regenerative capacity when compared to diabetic group. Melatonin showed superior results regarding the histomorphological structure of SMGs.

Conclusion

Melatonin and i-PRF can be possible candidates for improvement of wound healing events in SMGs of diabetic rats.

Challenges of Engineering Biomimetic Dental and Paradental Tissues

BACKGROUND

Loss of the dental and paradental tissues resulting from trauma, caries or from systemic diseases considered as one of the most significant and frequent clinical problem to the healthcare professionals. Great attempts have been implemented to recreate functionally, healthy dental and paradental tissues in order to substitute dead and diseased tissues resulting from secondary trauma of car accidents, congenital malformations of cleft lip and palate or due to acquired diseases such as cancer and periodontal involvements.

METHOD

An extensive literature search has been done on PubMed database from 2010 to 2019 about the challenges of engineering a biomimetic tooth (BioTooth) regarding basic biology of the tooth and its supporting structures, strategies, and different techniques of obtaining biological substitutes for dental tissue engineering.

RESULTS

It has been found that great challenges need to be considered before engineering biomimetic individual parts of the tooth such as enamel, dentin-pulp complex and periodontium. In addition, two approaches have been adopted to engineer a BioTooth. The first one was to engineer a BioTooth as an individual unit and the other was to engineer a BioTooth with its supporting structures.

CONCLUSION

Engineering of BioTooth with its supporting structures thought to be in the future will replace the traditional and conventional treatment modalities in the field of dentistry. To accomplish this goal, different cell lines and growth factors with a variety of scaffolds at the nano-scale level are now in use. Recent researches in this area of interest are dedicated for this objective, both in vivo and in vitro. Despite progress in this field, there are still many challenges ahead and need to be overcome, many of which related to the basic tooth biology and its supporting structures and some others related to the sophisticated techniques isolating cells, fabricating the needed scaffolds and obtaining the signaling molecules.

Gingival-derived mesenchymal stem cells: An endless resource for regenerative dentistry

The gingiva, the masticatory portion of the oral mucosa, is excised and discarded frequently during routine dental treatments and following tooth extraction, dental crown lengthening, gingivectomy and periodontal surgeries. Subsequent to excision, healing eventually happens in a short time period after gingival surgery. Clinically, the gingival tissue can be collected very easily and, in the laboratory, it is also very easy to isolate gingival-derived mesenchymal stem cells (GMSCs) from this discarded gingival tissue. GMSCs, a stem cell population within the lamina propria of the gingival tissue, can be isolated from attached and free gingiva, inflamed gingival tissues, and from hyperplastic gingiva. Comparatively, they constitute more attractive alternatives to other dental-derived mesenchymal stem cells due to the availability and accessibility of gingival tissues. They have unique immunomodulatory functions and well-documented self-renewal and multipotent differentiation properties. They display positive signals for Stro-1, Oct-4 and SSEA-4 pluripotency-associated markers, with some co-expressing Oct4/Stro-1 or Oct-4/SSEA-4. They should be considered as the best stem cell source for cell-based therapies and regenerative dentistry. The clinical use of GMSCs for regenerative dentistry represents an attractive therapeutic modality. However, numerous biological and technical challenges need to be addressed prior to considering transplantation approaches of GMSCs as clinically realistic therapies for humans.

[Construction of injectable tissue engineered adipose tissue with fibrin glue scaffold and human adipose-derived stem cells transfected by lentivirus vector expressing hepatocyte growth factor]

Objective

To discuss the possibility of constructing injectable tissue engineered adipose tissue, and to provide a new approach for repairing soft tissue defects.

Methods

Human adipose-derived stem cells (hADSCs) were extracted from the lipid part of human liposuction aspirate by enzymatic digestion and identified by morphological observation, flow cytometry, and adipogenic induction. The hADSCs underwent transfection by lentivirus vector expressing hepatocyte growth factor and green fluorescent protein (HGF-GFP-LVs) of different multiplicity of infection (MOI, 10, 30, 50, and 100), the transfection efficiency was calculated to determine the optimum MOI. The hADSCs transfected by HGF-GFP-LVs of optimal MOI and being adipogenic inducted were combined with injectable fibrin glue scaffold, and were injected subcutaneously into the right side of the low back of 10 T-cell deficiency BALB/c female nude mice (transfected group); non-HGF-GFP-LVs transfected hADSCs (being adipogenic inducted) combined with injectable fibrin glue scaffold were injected subcutaneously into the left side of the low back (untransfected group); and injectable fibrin glue scaffold were injected subcutaneously into the middle part of the neck (blank control group); 0.4 mL at each point. Twelve weeks later the mice were killed and the implants were taken out. Gross observation, wet weight measurement, HE staining, GFP fluorescence labeling, and immunofluorescence staining were performed to assess the in vivo adipogenic ability of the seed cells and the neovascularization of the grafts.

Results

The cultured cells were identified as hADSCs. Poor transfection efficiency was observed in MOI of 10 and 30, the transfection efficiency of MOI of 50 and 100 was more than 80%, so the optimum MOI was 50. Adipose tissue-like new-born tissues were found in the injection sites of the transfected and untransfected groups after 12 weeks of injection, and no new-born tissues was found in the blank control group. The wet-weight of new-born tissue in the transfected group [(32.30±4.06) mg] was significantly heavier than that of the untransfected group [(25.27±3.94) mg] ( t=3.929, P=0.001). The mature adipose cells in the transfected group [(126.93±5.36) cells/field] were significantly more than that in the untransfected group [(71.36±4.52) cells/field] ( t=30.700, P=0.000). Under fluorescence microscopy, some of the single cell adipocytes showed a network of green fluorescence, indicating the presence of GFP labeled exogenous hADSCs in the tissue. The vascular density of new-born tissue of the transfected group [(16.37±2.76)/field] was significantly higher than that of the untransfected group [(9.13±1.68)/field] ( t=8.678, P=0.000).

Conclusion

The hADSCs extracted from the lipid part after liposuction can be used as seed cells. After HGF-GFP-LVs transfection and adipose induction, the hADSCs combined with injectable fibrin glue scaffold can construct mature adipose tissue in vivo, which may stimulate angiogenesis, and improve retention rate of new-born tissue.