Cyclic mechanical pressure‐loading alters epithelial homeostasis in a three‐dimensional in vitro oral mucosa model: clinical implications for denture‐wearers

Abstract

Denture-wearing affects the quality and quantity of epithelial cells in the underlying healthy oral mucosa. The physiologic mechanisms, however, are poorly understood. This study aimed to compare histologic changes and cellular responses of an epithelial cell layer to cyclic mechanical pressure-loading mimicking denture-wearing using an organotypic culture system to develop a three-dimensional in vitro oral mucosa model (3DOMM). Primary human oral keratinocytes and fibroblasts were serially grown in a monolayer culture, and cell viability was measured under continuous cyclic mechanical pressure (50 kPa) for 7 days (cycles of 60 min on, 20 s off to degas and inject air). Upon initiation of an air-liquid interface culture for epithelial stratification, the cyclic pressure, set to the mode above mentioned, was applied to the 3DOMMs for 7 days. Paraffin-embedded 3DOMMs were examined histologically and immunohistochemically. In the monolayer culture, the pressure did not affect the viability of oral keratinocytes or fibroblasts. Few histologic changes were observed in the epithelial layer of the control and pressure-loaded 3DOMMs. Immunohistochemical examination, however, revealed a significant decrease in Ki-67 labelling and an increase in filaggrin and involucrin expression in the suprabasal layer of the pressure-loaded 3DOMMs. Pressure-loading attenuated integrin β1 expression and increased matrix metalloproteinase-9 activity. Incomplete deposition of laminin and type IV collagen beneath the basal cells was observed only in the pressure-loaded 3DOMM. Cyclic pressure-loading appeared to disrupt multiple functions of the basal cells in the 3DOMM, resulting in a predisposition towards terminal differentiation. Thus, denture-wearing could compromise oral epithelial homeostasis.

Influence of mandibular distal extension implant-supported removable partial dentures on the force exerted on maxillary anterior teeth

“…Stromberg et al reported that the pressure applied to the underlying mucosa was in the range of approximately 4-56 kPa [21]. An in vitro study by Shiomi et al found that repeated loading of 50 kPa to a threedimensional sheet of alveolar ridge mucosa increased the level of inflammatory substances that can cause ridge absorption [22]. The results of the present study suggest that the pressure applied to the underlying mucosa can be reduced by using implants to support the dental prosthesis, and may also suppress alveolar ridge resorption.…”

Crosstalk between oral squamous cell carcinoma cells and cancer-associated fibroblasts via the TGF-β/SOX9 axis in cancer progression

“…The patients were provided sufficient information regarding this study, and all participating individuals signed an informed consent form. Primary normal oral fibroblasts (NOFs) were established using an explant culture technique and were serially cultured as previously described [21] . NOFs from passages 3 to 5 were used in the study as a control.…”

“…We previously established a system for oral mucosa tissue engineering to investigate pathophysiological lesions specific to the oral cavity. This system provides a biomimetic 3D in vitro model containing OSCC cells and CAFs [21] .…”

Effects of C-xylopyranoside derivative on epithelial regeneration in an in vitro 3D oral mucosa model

“…The 3DOMM was fabricated according to a previous study with minor modifications. 26) Briefly, after filling a six-well tissue culture insert (Greiner Bio, Roskilde, Denmark) with 1 mL acellular type I collagen matrix (Nitta gelatin, Osaka, Japan), a mixture of 3 mL collagen matrix solution and 5.0 × 10 5 OFs was placed on top of the solidified acellular collagen matrix. After the mixture solidified, 22 mL DMEM containing 10% FBS was added to create a submerged culture condition.…”