Human Periodontal Ligament Stem Cells Response to Titanium Implant Surface: Extracellular Matrix Deposition.

Thangavelu Soundara Rajan,Adriano Piattelli,Jacopo Pizzicannella,Guya Diletta Marconi,Luigia Fonticoli,Francesca Diomede,Oriana Trubiani,Ylenia Della Rocca

doi:10.3390/biology10090931

Abstract

Simple SummaryThe extracellular matrix (ECM) is a fundamental component of tissues and organs, providing the structural and non-structural support that leads to the bone osseointegration. Understanding the mechanisms of ECM components modulation is essential for developing novel strategies for tissue engineering and regenerative medicine and in particular for the dental implant surface design. The release of ECM components by cells is the first step that leads to the early stage of bone formation. The present work is focused on the modulation of ECM components expression by human periodontal ligament stem cells (hPDLSCs) cultured on two different dental implant surfaces, sandblasted (CTRL) and dual acid-etched (TEST). The effects were evaluated by means of the morphological observations and protein and gene expression. The results demonstrated that the rough surface of titanium dental implant can enhance the expression of ECM molecules and osteogenic markers in hPDLSCs. The surface topography is of vital importance as it regulates cell response. It can be considered one of the main factors that influence the success of a dental implant. The influence of surface topography on osseointegration could lead to short healing times and a better quality of oral rehabilitation and patient life.The major challenge for dentistry is to provide the patient an oral rehabilitation to maintain healthy bone conditions in order to reduce the time for loading protocols. Advancement in implant surface design is necessary to favour and promote the osseointegration process. The surface features of titanium dental implant can promote a relevant influence on the morphology and differentiation ability of mesenchymal stem cells, induction of the osteoblastic genes expression and the release of extracellular matrix (ECM) components. The present study aimed at evaluating the in vitro effects of two different dental implants with titanium surfaces, TEST and CTRL, to culture the human periodontal ligament stem cells (hPDLSCs). Expression of ECM components such as Vimentin, Fibronectin, N-cadherin, Laminin, Focal Adhesion Kinase (FAK) and Integrin beta-1 (ITGB1), and the osteogenic related markers, as runt related transcription factor 2 (RUNX2) and alkaline phosphatase (ALP), were investigated. Human PDLSCs cultured on the TEST implant surface demonstrated a better cell adhesion capability as observed by Scanning Electron Microscopy (SEM) and immunofluorescence analysis. Moreover, immunofluorescence and Western blot experiments showed an over expression of Fibronectin, Laminin, N-cadherin and RUNX2 in hPDLSCs seeded on TEST implant surface. The gene expression study by RT-PCR validated the results obtained in protein assays and exhibited the expression of RUNX2, ALP, Vimentin (VIM), Fibronectin (FN1), N-cadherin (CDH2), Laminin (LAMB1), FAK and ITGB1 in hPDLSCs seeded on TEST surface compared to the CTRL dental implant surface. Understanding the mechanisms of ECM components release and its regulation are essential for developing novel strategies in tissue engineering and regenerative medicine. Our results demonstrated that the impact of treated surfaces of titanium dental implants might increase and accelerate the ECM apposition and provide the starting point to initiate the osseointegration process.

Highlights

Titanium represents the gold standard for the production of endosseous dental implants due to its characteristics that make it biocompatible, resistant to corrosion and possess excellent mechanical and chemical properties
The aim was to evaluate the efficacy of different titanium surfaces treatment on human periodontal ligament stem cells (hPDLSCs), used as an in vitro cell system, to assess the cell morphology, adhesion capacity and the extracellular matrix (ECM) components release
Human PDLSCs cultured on TEST surface showed a slightly better morphology compared to Control surface (CTRL) sample

Summary

Introduction

Titanium represents the gold standard for the production of endosseous dental implants due to its characteristics that make it biocompatible, resistant to corrosion and possess excellent mechanical and chemical properties. Titanium surface topography can modify the cell attachment, spreading, proliferation, orientation and protein level expression. Osseointegration is the main goal to reach after implant rehabilitation, the most important features allowing the osseointegration are primary stability, the type of native bone and the surgical techniques other than the surface morphology of the used dental implant [2,3,4]. The osseointegration process after dental implant insertion is strictly related to the immuno-inflammatory reactions. The proinflammatory wound-healing phase precedes a regenerative phase in which down-regulation of inflammation and up-regulation of osteogenesis related genes occur during the early osseointegration process, multinucleated giant cells appear to be an integral part of the normal osseointegration event [5,6]

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