Tissue engineered scaffold for periodontal regeneration: laboratorial and preclinical characterization

Periodontal Disease is an inflammatory disease that constitutes an important health problem in Veterinary and in Human Medicine, due to its enormous prevalence and life threatening implications on systemic health [1]. Currently, is treated by gingival surgery, root planning and conditioning, application of growth and differentiation factors or filler materials and guided tissue regeneration. These therapies have several drawbacks, namely, the inefficacy of avoiding the epithelial tissue growth thought the radicular surface and bone resorption and ankilosis, which inhibits the formation of a functional periodontal ligament [2]. Tissue Engineering strategies using a combination of scaffolds and mesenchymal stem cells has paved the way for new therapies [3,4].

Our goal was to develop a construct for periodontal regeneration based on culturing canine adipose-derived stem cells (cASCs) [5] onto a double layer scaffold comprising a starch+poly(e-caprolactone) (SPCL) membrane, which acts as a guided tissue regeneration barrier, and a SPCL fibre mesh functionalized with osteoconductive silanol groups [6].

The SPCL membrane was obtained by solvent casting and then combined with a wet-spun fibre mesh (WSFM) with/without silanol groups. Canine ASCs (cASCs) were obtained from subcutaneous adipose tissue. The proliferation of cASCs seeded/cultured onto the scaffold was studied by dsDNA quantification and SEM. Osteogenic differentiation on the WSFM was assessed by ALP quantification, real time RT-PCR (osteoblastic markers) and histology (Alizarin Red and Lévai Laczkó stainings).

Further in this work, the performance of the SPCL and SPCL-Si scaffolds was assessed in a mandibular rodent model and compared with collagen commercial membranes (positive control) and empty defects (negative control). After 8 weeks of implantation, the explants were processed by the Donath technique and the new bone formation quantified.

Cell culturing experiments showed that the developed materials provide a good support for cASCs  adhesion and proliferation. ALP activity increasing until 21^th day and also the calcium content revealing osteoconductivity and bioactivity of the SPCL scaffolds, particularly those functionalized with Si groups. Osteogenic markers (e.g. Osteocalcin) were also expressed by cASCs cultured in the constructs. Histomorphometrical analysis revealed that the SPCL-Si scaffolds induced higher bone formation compared to collagen materials and empty defects.

This bioactive double layer scaffold revealed the potential to be used in TE approaches to reach periodontal regeneration. The functionalization of the wet-spun fibre with silanol groups confers an osteoinductive and osteoconductive potential. Future studies using other animal models are required to demonstrate the full potential of this construct for periodontal regeneration.