Aligned polymer Scaffolds in Periodontal Tissue Engineering

Introduction:
Periodontal disease is characterized by progressive gingival inflammation and degradation of the periodontal ligament and alveolar bone. Periodontal treatments, including guided tissue regeneration, do not always give full tissue regeneration Recently, several studies have investigated the use of tissue engineering to facilitate periodontal tissue regeneration. Much interest has been directed towards the construction of scaffolds which reflect the aligned topographic arrangement of collagen fibres in native periodontal ligament. Mechanical loading is a critical component when engineering load-bearing tissues as appropriate biomechanical cues are essential for extracellular matrix (ECM) organization and alignment.

Objectives:
The aims were to investigate the effect of fibre alignment of electrospun poly-L-lactic acid (PLLA) mats on the biological response of periodontal ligament fibroblasts (PDLF) and to study static and cyclic tension forces on PDLF gene expression.

Methods:
Aligned and random PLLA scaffolds were fabricated, seeded with PDLF and cultured for varying periods of time. PDLF gene expression and ECM of the engineered tissues were analysed by quantitative real-time polymerase chain reaction (qPCR), scanning electron microscopy (SEM), and immunohistochemistry. Engineered PDL constructs were subjected to static strains of 0-20% for 3 h in individual, custom-made, loading chambers. PDLF were cultured in collagen gels and subjected to cyclic loading using Flexcell loading system with a dynamic uniaxial strain at 1 Hz for 8-48 h. After loading, PDLF gene expression was assessed by qPCR.

Results:
On aligned scaffolds, PDLF were elongated shape and oriented along the long-axis of the fibres and showed a higher matrix deposition. Mechanical strain up regulated Collagen 1, Periostin, IL-6 and scleraxis on aligned-fibre scaffolds. In summary, fibre alignment influenced PDLF phenotype and also modulated PDLF gene expression in response to mechanical strain.
Conclusion:
In conclusion, appropriate fibre alignment is a desirable feature to consider in the design of scaffolds for periodontal tissue engineering.

دلال حزام العتيبي

, D. Alotaibi *, K. Legerlotz , E. Jones , G. Riley2, G. Griffiths , P.V, Hatton , A. Crawford . 2013