Promotion of oral surgical wound healing using autologous mucosal cell sheets

Biofabrication Strategies for Oral Soft Tissue Regeneration

Gingival recession, a prevalent condition affecting the gum tissues, is characterized by the exposure of tooth root surfaces due to the displacement of the gingival margin. This review explores conventional treatments, highlighting their limitations and the quest for innovative alternatives. Importantly, it emphasizes the critical considerations in gingival tissue engineering leveraging on cells, biomaterials, and signaling factors. Successful tissue-engineered gingival constructs hinge on strategic choices such as cell sources, scaffold design, mechanical properties, and growth factor delivery. Unveiling advancements in recent biofabrication technologies like 3D bioprinting, electrospinning, and microfluidic organ-on-chip systems, this review elucidates their precise control over cell arrangement, biomaterials, and signaling cues. These technologies empower the recapitulation of microphysiological features, enabling the development of gingival constructs that closely emulate the anatomical, physiological, and functional characteristics of native gingival tissues. The review explores diverse engineering strategies aiming at the biofabrication of realistic tissue-engineered gingival grafts. Further, the parallels between the skin and gingival tissues are highlighted, exploring the potential transfer of biofabrication approaches from skin tissue regeneration to gingival tissue engineering. To conclude, the exploration of innovative biofabrication technologies for gingival tissues and inspiration drawn from skin tissue engineering look forward to a transformative era in regenerative dentistry with improved clinical outcomes.

Engineering Heterogeneous Tumor Models for Biomedical Applications

Tumor tissue engineering holds great promise for replicating the physiological and behavioral characteristics of tumors in vitro. Advances in this field have led to new opportunities for studying the tumor microenvironment and exploring potential anti-cancer therapeutics. However, the main obstacle to the widespread adoption of tumor models is the poor understanding and insufficient reconstruction of tumor heterogeneity. In this review, the current progress of engineering heterogeneous tumor models is discussed. First, the major components of tumor heterogeneity are summarized, which encompasses various signaling pathways, cell proliferations, and spatial configurations. Then, contemporary approaches are elucidated in tumor engineering that are guided by fundamental principles of tumor biology, and the potential of a bottom-up approach in tumor engineering is highlighted. Additionally, the characterization approaches and biomedical applications of tumor models are discussed, emphasizing the significant role of engineered tumor models in scientific research and clinical trials. Lastly, the challenges of heterogeneous tumor models in promoting oncology research and tumor therapy are described and key directions for future research are provided.

Recent trends and perspectives in reconstruction and regeneration of intra/extra-oral wounds using tissue-engineered oral mucosa equivalents

Many conditions, including cancer, trauma, and congenital anomalies, can damage the oral mucosa. Multiple cultures of oral mucosal cells have been used for biocompatibility tests and oral biology studies. In recent decades, the clinical translation of tissue-engineered products has progressed significantly in developing tangible therapies and inspiring advancements in medical science. However, the reconstruction of an intraoral mucosa defect remains a significant challenge. Despite the drawbacks of donor-site morbidity and limited tissue supply, the use of autologous oral mucosa remains the gold standard for oral mucosa reconstruction and repair. Tissue engineering offers a promising solution for repairing and reconstructing oral mucosa tissues. Cell- and scaffold-based tissue engineering approaches have been employed to treat various soft tissue defects, suggesting the potential clinical use of tissue-engineered oral mucosa (TEOMs). In this review, we first cover the recent trends in the reconstruction and regeneration of extra-/intra-oral wounds using TEOMs. Next, we describe the current status and challenges of TEOMs. Finally, future strategic approaches and potential technologies to support the advancement of TEOMs for clinical use are discussed.

Promotion of skin wound healing using hypoimmunogenic epidermal cell sheets

Objective

The physiological process of wound healing is dynamic, continuous, and intricate. Nowadays, full-thickness burn wounds are treated by autologous skin transplantation. Unfortunately, when substantial burns develop, there are fewer donor sites accessible, making it difficult to satisfy the requirement for large-scale skin transplants and increasing the risk of patient mortality. This study investigated the possibility of using a newly created hypoimmunogenic epidermal cell sheet to heal skin wounds.

Methods

Transfection with lentivirus was used to generate Keratinocytes (KCs) that overexpress Indoleamine 2,3-Dioxygenase (IDO). Western blotting and quantitative polymerase chain reaction were used to measure IDO levels. To evaluate the function of IDO+ keratinocytes, CCK-8 and Transwell assays were performed. In cell sheet induction media, KCs and Fibroblasts (FBs) were cultured to yield epidermal cell sheets. The full-thickness skin excisions of BALB/c mice were transplanted with epidermal cell sheets. To assess the tumorigenicity of IDO+ keratinocytes, BALB/c nude mouse xenograft models were also used. CD3 and CD31 immunofluorescence labeling of wound tissue on day 12 to identify T lymphocyte infiltration and capillary development. ELISA measurement of IL-1 and TNF-α concentrations.

Results

IDO + keratinocytes dramatically enhanced the expression levels of IDO mRNA and protein, as well as the amount of kynurenine in the conditioned media of IDO+ keratinocytes, compared to the Control and NC groups. CD8+ T cell apoptosis was considerably greater in the IDO group than in the Control and NC groups. Nevertheless, the proliferation and migratory capabilities of IDO+ keratinocytes were not substantially different from those of the Control and NC groups. In vitro cultivation of the hypoimmunogenic epidermal cell sheet was effective. In vivo transplantation experiments demonstrated that IDO+ epidermal cell sheets can effectively promote wound healing without tumorigenicity, and IDO+ epidermal cell sheets may promote wound healing by decreasing the expression levels of inflammatory factors (TNF and IL-1) in wound tissue, decreasing CD3+ T lymphocytes, and increasing infiltration and new capillaries in wound tissue.

Conclusion

In this study, we successfully constructed the hypoimmunogenic epidermal cell sheet and demonstrated that the hypoimmunogenic epidermal cell sheet could accelerate wound healing.

Novel Strategies for Orofacial Soft Tissue Regeneration

Significance: Orofacial structures are indispensable for speech and eating, and impairment disrupts whole-body health through malnutrition and poor quality of life. However, due to the unique and highly specialized cell populations, tissue architecture, and healing microenvironments, regeneration in this region is challenging and inadequately addressed to date. Recent Advances: With increasing understanding of the nuanced physiology and cellular responses of orofacial soft tissue, novel scaffolds, seeded cells, and bioactive molecules were developed in the past 5 years to specifically target orofacial soft tissue regeneration, particularly for tissues primarily found within the orofacial region such as oral mucosa, taste buds, salivary glands, and masseter muscles. Critical Issues: Due to the tightly packed and complex anatomy, orofacial soft tissue injury commonly implicates multiple tissue types, and thus functional unit reconstruction in the orofacial region is more important than single tissue regeneration. Future Directions: This article reviews the up-to-date knowledge in this highly translational topic, which provides insights into novel biologically inspired and engineered strategies for regenerating orofacial component tissues and functional units.

Cancer-Associated Fibroblasts: The Origin, Biological Characteristics and Role in Cancer-A Glance on Colorectal Cancer

Simple Summary

Tumor microenvironment is a major contributor to tumor growth, metastasis and resistance to therapy. It consists of many cancer-associated fibroblasts (CAFs), which derive from different types of cells. CAFs detected in different tumor types are linked to poor prognosis, as in the case of colorectal cancer. Although their functions differ according to their subtype, their detection is not easy, and there are no established markers for such detection. They are possible targets for therapeutic treatment. Many trials are ongoing for their use as a prognostic factor and as a treatment target. More research remains to be carried out to establish their role in prognosis and treatment.

Abstract

The therapeutic approaches to cancer remain a considerable target for all scientists around the world. Although new cancer treatments are an everyday phenomenon, cancer still remains one of the leading mortality causes. Colorectal cancer (CRC) remains in this category, although patients with CRC may have better survival compared with other malignancies. Not only the tumor but also its environment, what we call the tumor microenvironment (TME), seem to contribute to cancer progression and resistance to therapy. TME consists of different molecules and cells. Cancer-associated fibroblasts are a major component. They arise from normal fibroblasts and other normal cells through various pathways. Their role seems to contribute to cancer promotion, participating in tumorigenesis, proliferation, growth, invasion, metastasis and resistance to treatment. Different markers, such as a-SMA, FAP, PDGFR-β, periostin, have been used for the detection of cancer-associated fibroblasts (CAFs). Their detection is important for two main reasons; research has shown that their existence is correlated with prognosis, and they are already under evaluation as a possible target for treatment. However, extensive research is warranted.

Osteopontin-derived synthetic peptide SVVYGLR upregulates functional regeneration of oral and maxillofacial soft-tissue injury

Wound healing in the oral and maxillofacial region is a complicated and interactive process. Severe mucosal or skeletal muscle injury by trauma or surgery induces worse healing conditions, including delayed wound closure and repair with excessive scar tissue. These complications lead to persistent functional impairment, such as digestive behavior or suppression of maxillofacial growth in infancy. Osteopontin (OPN), expressed in a variety of cells, is multifunctional and comprises a number of functional domains. Seven amino acids sequence, SVVYGLR (SV peptide), exposed by thrombin cleavage of OPN, has angiogenic activity and promotes fibroblast differentiation into myofibroblasts and increased expression of collagen type III. Additionally, synthetic SV peptide shows faster dermal and oral mucosal wound closure by facilitating cell motility and migratory activities in dermal- or mucosal-derived keratinocytes and fibroblasts. Moreover, cell motility and differentiation in myogenic cell populations are accelerated by SV peptide, which contributes to the facilitation of matured myofibers and scarless healing and favorable functional regeneration after skeletal muscle injury. SV peptide has high affinity with TGF-β, with potential involvement of the TGF-β/Smad signaling pathway. Clinical application of single-dose SV peptide could be a powerful alternative treatment option for excessive oral and maxillofacial wound care to prevent disadvantageous events.

Intralesional platelet-rich plasma injection promotes tongue regeneration following partial glossectomy in a murine model

BACKGROUND

We examined the regenerative efficacy of the activated platelet-rich plasma (PRP) concentrate administered by local injection in an animal model mimicking partial glossectomy for tongue cancer.

METHODS

Four-week-old mice were randomized to four groups; (1) a treatment-naïve control group, (2) a PRP group, (3) a hemiglossectomy group, and (4) a hemiglossectomy + PRP group. The activated PRP concentrate was injected into the deep layer of resected surfaces of mouse tongues immediately after excision, and tongue widths and lengths were measured on postoperative days (POD) 5 and 12. Gross tongue morphologies and microscopic findings were investigated. Inflammation and fibrous tissue areas were also measured, and immunohistochemical analysis was performed for c-kit, neurofilament, and S-100.

RESULTS

The activated PRP concentrate reduced wound scar contracture, promoted wound healing, and reduced inflammation and wound fibrosis. On POD 12, histologic findings in the hemiglossectomy + PRP group were similar to those in the normal control group, and the intensity of stem cell factor receptor c-kit expression was also significantly greater in the PRP group than in the hemiglossectomy group on POD 12. Immunohistochemical staining revealed S100 and neurofilament expressions in the hemiglossectomy + PRP group were significantly more intense than in the hemiglossectomy group.

CONCLUSION

Intralesional activated PRP concentrate injection has potential use for tongue regeneration, wound healing, and neural regeneration with minimal scarring after partial glossectomy.

Regenerative medicine for end-stage fibrosis and tissue loss in the upper aerodigestive tract: a twenty-first century review

OBJECTIVE

This review assesses regenerative medicine of the upper aerodigestive tract during the first two decades of the twenty-first century, focusing on end-stage fibrosis and tissue loss in the upper airways, salivary system, oropharynx and tongue.

METHOD

PubMed, Embase, Google Scholar, Cochrane Library, Medline and clinicaltrials.org were searched from 2000 to 2019. The keywords used were: bioengineering, regenerative medicine, tissue engineering, cell therapy, regenerative surgery, upper aerodigestive tract, pharynx, oropharynx, larynx, trachea, vocal cord, tongue and salivary glands. Original studies were subcategorised by anatomical region. Original human reports were further analysed. Articles on periodontology, ear, nose and maxillofacial disorders, and cancer immunotherapy were excluded.

RESULTS

Of 716 relevant publications, 471 were original studies. There were 18 human studies included, within which 8 reported airway replacements, 5 concerned vocal fold regeneration and 3 concerned salivary gland regeneration. Techniques included cell transplantation, injection of biofactors, bioscaffolding and bioengineered laryngeal structures.

CONCLUSION

Moderate experimental success was identified in the restoration of upper airway, vocal fold and salivary gland function. This review suggests that a shift in regenerative medicine research focus is required toward pathology with a higher disease burden.

Synthetic peptide SVVYGLR upregulates cell motility and facilitates oral mucosal wound healing

Osteopontin-derived SVVYGLR (SV) 7-amino-acid sequence is a multifunctional and synthetic SV peptide implicated in angiogenesis, production of collagen III, and fibroblast differentiation into myofibroblasts. This study investigated the effect of the SV peptide on mucosal wound healing activity. Normal human-derived gingival fibroblasts (NHGF) and human oral mucosa keratinocytes (HOMK) were used for in vitro experiments. In addition, an oral punch wound was prepared at the buccal mucosa in male rats aged 11 weeks, and we evaluated the effect of local injection of SV peptide on wound healing. The synthetic SV peptide showed no influence on the proliferation and adhesion properties of NHGF and HOMK, but it enhanced the cell motility and migration activities. TGF-β1 receptor inhibitor, SB431542 or SB505124, substantially suppressed the SV peptide-induced migration activity, suggesting an involvement of TGF-β1 receptor activation. Furthermore, SV peptide accelerated the healing process of an in vivo oral wound model, compared with control groups. Further immunohistological staining of wound tissue revealed that an increase in capillary growth and the greater number of fibroblasts and myofibroblasts that migrated into the wound area might contribute to the facilitation of the healing process produced by the SV peptide. The SV peptide has beneficial effects on oral wound healing through enhancement of the earlier phase consisting of angiogenesis and remodeling with granulation tissue. The synthetic SV peptide can be a useful treatment option, particularly for intractable mucosal wounds caused by trauma or surgery for progressive lesions such as oral cancer.

Regeneration of lingual musculature in rats using myoblasts over porcine bladder acellular matrix

OBJECTIVES

To use tissue engineering muscle repair (TEMR) for regenerating the lingual musculature of hemiglossectomized rats using neonatal myoblasts (NM) on porcine acellular urinary bladder matrix (AUBM).

MATERIAL AND METHODS

The study used 80 male rats. A volumetric muscle loss (VML) injury was created on the left side of the tongue. The rats were randomized into four groups: Group 1 (AUBM + myoblasts); Group 2 (AUBM); Group 3 (myoblasts); and Group 4 (control). NM were obtained from neonatal rats. The animals were weighed on day 0 and just before euthanasia. Five rats in each group were euthanized at days 2, 14, 28, and 42; the tongues were prepared for morphometric analysis, postoperative left hemitongue weight, and immunohistochemical analysis (desmin, CD-31, and anti-neurofilament).

RESULTS

The weight gain from greatest to least was as follows: AUBM + myoblasts > myoblasts > AUBM > control. The tongue dorsum occupied by VML, and difference in mg between control side and intervened side from least to great was as follows: AUBM + myoblasts < myoblasts < AUBM < control. The order from highest to lowest antibody positivity was as follows: AUBM + myoblasts > myoblasts > AUBM > control.

CONCLUSION

The use of porcine AUBM and NM for the regeneration of lingual musculature was found to be an effective TEMR treatment for repairing tongue VML injury.

Ex vivo culture of head and neck cancer explants in cell sheet for testing chemotherapeutic sensitivity

PURPOSE

Tumor explant culture systems can mimic the in vivo tumor microenvironment, proposing as a substitute for preclinical studies for prediction of individual treatment response. Therefore, our study evaluated the potential usefulness of ex vivo tumor explants culture assembled into the cell sheets by anticancer drug screening in patients with head and neck squamous cell carcinoma (HNSCC).

METHODS

Our model included tumor explants incorporated into cell sheet composing of epithelium and subepithelial stroma using tumor and mucosal samples obtained from the HNSCC patients who underwent surgery. Cell growth, viability, and hypoxia were measured by cell counting kit-8, live/dead assay, propidium iodide, and LOX-1 staining, and were compared among the different treatment groups with vehicle, cisplatin or docetaxel.

RESULTS

Tumor explants stably survived in the cell sheet over 10 days after explantation, whereas most of the explants in non-matrix culture became nonviable within 5-8 days with the significant daily decrease of viability. The live tissue areas of tumor explants in the cell sheet maintained over 30 days without significant changes although hypoxic cell areas gradually increased up to 5 days. Tissue viability and live cancer tissue areas significantly decreased after the treatment of cisplatin or docetaxel in the dose and time-dependent manners.

CONCLUSION

Our cell sheet-based tumor explants model might be applied to the reliable ex vivo screening for anticancer chemotherapeutics for HNSCC.

Lactobacillus reuteri extracts promoted wound healing via PI3K/AKT/β-catenin/TGFβ1 pathway

BACKGROUND

The balance of oral microbiomes is crucial to maintain oral health. Microecological imbalance can impair the function of mesenchymal stem cells (MSCs) and lead to delay wound healing. Probiotics is a promising prevention approach for the treatment of oral inflammatory diseases caused by a bacterial infection. However, the effect of probiotics on oral MSCs and wound healing is unclear. In the present study, we used one type of probiotics Lactobacillus reuteri extracts to determine whether bacterial extracts could regulate the functions of gingiva MSCs (GMSCs) and promote wound healing.

METHODS

Lactobacillus reuteri was prepared with bacterial extracts using ultrasonic crushing apparatus. The effects of Lactobacillus reuteri extracts on GMSCs were tested using the cell scratch migration, alkaline phosphatase (ALP) activity, alizarin red staining, cell counting kit-8, real-time PCR, and western blot assays. To investigate the role of Lactobacillus reuteri extracts in the wound in mice, the wound position of bilateral mesial gingival of the maxillary first molar was established, the wound area with a size of 1 mm × 2 mm and the full thickness gingiva was removed. Mice with wound were randomly distributed to two groups: injection of 0.9% NaCl (NS group) or injection of 50 μg/ml bacterial extracts.

RESULTS

We discovered that 50 μg/ml Lactobacillus reuteri extracts increased the capacities of migration, expression of stem cell markers, osteogenic differentiation, and proliferation of GMSCs. In addition, local injection of 50 μg/ml bacterial extracts could promote wound-healing process in mice models. Mechanistically, we found that Lactobacillus reuteri extracts accelerated the process of wound healing via PI3K/AKT/β-catenin/TGFβ1 pathway.

CONCLUSIONS

These data showed that Lactobacillus reuteri extracts could activate the potentials of GMSCs, thus promote wound healing. Our discovery provided the insight of the underlying mechanism activating functions of MSCs and identified Lactobacillus reuteri extracts as a potential therapeutic strategy for accelerating oral wound and potential application in the future dental clinic.

Promotion of skin wound healing using prevascularized oral mucosal cell sheet

BACKGROUND

This study examined the potential use of our newly developed prevascularized oral mucosal cell sheet for the treatment of skin wounds.

METHODS

Mucosal cell sheets containing cultured keratinocytes and plasma fibrin without (K sheet) or with a mixture of fibroblasts and endothelial progenitor cells (PV sheet) were transplanted into full-thickness skin excisional wounds of nude mice.

RESULTS

This technique was successful for in vitro culture; expanding keratinocytes, fibroblasts, and endothelial progenitor cells; and generating prevascularized mucosal cell sheets. Cell sheets promoted in vivo wound healing with rapid wound closure and less scarring compared to controls. This result was more apparent in the PV than the K sheet (P < .05). Wounds covered with cell sheets showed less expression of TGFB1, ACTA2, and FN1 mRNAs than the controls (P < .05).

CONCLUSION

The prevascularized mucosal cell sheet showed in vivo efficacy and tissue plasticity in cutaneous wounds by promoting accelerated healing.

Treatment of intractable oral ulceration with an oral mucosa equivalent

The current use of steroids or pharmacological immunomodulators for the treatment of intractable oral ulceration is ineffective, necessitating newer cell-based therapeutic approaches. We examined the potential efficacy of an oral mucosa equivalent developed in this study in an in vivo model of repeat major oral ulceration mimicking the intractable oral ulceration observed clinically. Oral mucosal samples and plasma fibrin were obtained from Sprague-Dawley rats. The oral mucosa equivalents were prepared with cultured mucosal keratinocytes and plasma fibrin mixed with cultured fibroblasts. Ulcers were chemically induced on the rat buccal mucosa thrice in 3 weeks and covered with or without mucosa equivalents. Gross and microscopic findings and mRNA expression levels were compared between the ulcer control and mucosa equivalent groups. Oral mucosal keratinocytes and fibroblasts were cultured in vitro to achieve high viability and colony-forming efficiency. The equivalents showed epithelial and subepithelial structures similar to those of oral mucosa and exhibited high p63 positivity. In the in vivo study, ulceration was resolved earlier without significant granulation or scarring in the equivalent group than in control group (p < 0.05). Microscopic examinations revealed rapid re-epithelialization and less fibrosis in the equivalent group than in the control group (p < 0.05). Mucosa equivalent-covered ulcers showed histological characteristics similar to those of the normal buccal mucosa and exhibited lower expression of TGFB1, ACTA2, and FN1 mRNAs than the control group. The in vitro-engineered oral mucosa equivalent promotes ulcer healing without scarring and functional deficits. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1779-1785, 2019.

Use of a pre-vascularised oral mucosal cell sheet for promoting cutaneous burn wound healing

Pre-vascularised cell sheets have been used to promote early angiogenesis and graft survival. However, the use of pre-vascularised mucosal cell sheets for burn wounds has been rarely evaluated. Therefore, we examined the applicability of an oral pre-vascularised mucosal cell sheet that we had previously developed for the treatment of cutaneous burn wounds.

Methods: Mucosal keratinocytes, fibroblasts, and endothelial progenitor cells were isolated from the oral mucosa and peripheral blood and were expanded in vitro. Mucosal cell sheets were generated by seeding cultured keratinocytes onto a mixture of fibroblasts, endothelial cells, and fibrin. Third-degree burn wounds were created on the backs of rats and were covered with the cell sheets, skin grafts, or silastic sheets as a control. Gross and microscopic findings and gene expression profiles of wounds were compared among the groups.

Results: CD31-positive microvessels were observed in the fibrin-matrix layer of the cell sheet. In the cutaneous burn wound model, the cell sheets promoted wound healing, with accelerated wound closure and less scarring than with silastic sheets and skin grafts. The cell sheets had more microvessels and proliferating cells and less neutrophil infiltration and fibrotic features than the controls or skin grafts. The cell sheet induced higher mRNA expression of KRT14, VEGFA, IL10, and AQP3 and lower mRNA expression of TGFB1, IL6, ICAM1, ACTA2, and FN1 than did the controls or skin grafts.

Conclusions: The pre-vascularised mucosal cell sheet promotes cutaneous burn wound healing.

Development of an in vitro cell-sheet cancer model for chemotherapeutic screening

Epithelial cancer grows in vivo in a microenvironment that comprises tumour, stroma, and immune cells. A three-dimensional (3D) culture model might be able to mimic the tumour microenvironment in vivo; therefore, we developed a new 3D epithelial cancer model using in vitro cell-sheet engineering and compared the results of treatment with several chemotherapeutic drugs among the 3D cell-sheet model, spheroid culture, and 2D cell culture.

Methods: The cell sheet comprised keratinocytes and a plasma fibrin matrix containing fibroblasts. Cancer spheroids with or without cancer-associated fibroblasts (CAFs) were interposed between the keratinocytes and fibrin layer. Cell growth, viability, and hypoxia were measured using the cell counting kit-8, LIVE/DEAD assay, and propidium iodide and LOX-1 staining. The morphology, invasion, and mRNA and protein expression were compared among the different cell culture models.

Results: Enhanced resistance to sorafenib and cisplatin by cancer spheroids and CAFs was more easily observed in the 3D than in the 2D model. Invasion by cancer-CAF spheroids into the fibrin matrix was more clearly observed in the 3D cell sheet. The expansion of viable cancer cells increased in the 3D cell sheet, particularly in those with CAFs, which were significantly inhibited by treatment with 10 μM sorafenib or 20 μM cisplatin (P < 0.05). TGF-β1, N-cadherin, and vimentin mRNA and protein levels were higher in the 3D cell-sheet model.

Conclusions: The 3D cell sheet-based cancer model could be applied to in vitro observation of epithelial cancer growth and invasion and to anticancer drug testing.

Plasticity of oral mucosal cell sheets for accelerated and scarless skin wound healing

OBJECTIVES

Wound healing is generally faster and associated with less scarring in the oral mucosa than in the skin. Although rarely studied, oral mucosa equivalents may contribute to rapid, scarless cutaneous wound healing. Therefore, we examined the potential utility of our newly developed oral mucosal cell sheet in skin wound healing.

MATERIALS AND METHODS

Oral mucosa and skin samples were obtained from surgical patients and Sprague-Dawley rats. Keratinocytes and fibroblasts were primarily cultured for in vitro cell expansion. Mucosa and skin equivalents were produced with a mixture of cultured fibroblasts and autologous fibrin from plasma and seeding keratinocytes. Mucosal and skin cell sheets were transplanted in full-thickness excisional wounds of rat skin with control wounds. Gross, histological, and molecular characteristics of wound healing according to different postsurgical days were compared in control and cell sheet-covered wounds.

RESULTS

Keratinocytes and fibroblasts derived from the oral mucosa were cultured faster than those derived from the skin. The in vitro-engineered oral mucosa and skin equivalents were successfully produced using complete autologous mucosa or skin and plasma fibrin, showing similarity to the histological characteristics of the skin or mucosa. In the in vivo rat model, the oral mucosal and skin cell sheet promoted wound healing with early wound closure and less scarring. The cell sheet-treated wounds showed lower TGF-β1, α-smooth muscle actin, and fibronectin mRNA expression than the control wounds.

CONCLUSIONS

The oral mucosal cell sheet demonstrated in vivo tissue plasticity through good adaptation to skin wounds, contributing to accelerated and scarless healing.

Accelerated oral wound healing using a pre-vascularized mucosal cell sheet

Cell sheets with pre-vascularization have recently been developed but remain relatively untested in oral wound healing. Therefore, we examined the potential utility of our newly developed pre-vascularized mucosal cell sheets in oral wound healing. Mucosal keratinocytes, fibroblasts, and endothelial progenitor cells were primarily cultured for in vitro cell expansion from mucosa and blood of Sprague-Dawley rats. Mucosal cell sheets were generated using cultured keratinocytes and plasma fibrin (K sheet) or keratinocytes and a mixture of fibrin, fibroblasts, and endothelial cells (PV sheet). Autologous sheets were transplanted on deep wounds in the buccal region of rats. The gross and histological characteristics of wound healing were compared among control wound, K sheet, and PV sheet groups. We successfully cultured and expanded keratinocytes, fibroblasts, and endothelial progenitor cells in vitro for generating mucosal cell sheets with or without pre-vascularization. In the in vivo oral wound model, compared with the control wound, the PV sheet group exhibited rapid wound closure more prominently than the K sheet group. The histological healing in the PV sheet group was similar to that in rat normal buccal mucosa without fibrosis. The pre-vascularized mucosal cell sheet exhibited in vivo efficacy in oral wound healing by promoting accelerated healing.