Research Article: hPL promotes osteogenic differentiation of stem cells in 3D scaffolds

Date Published: May 7, 2019

Publisher: Public Library of Science

Author(s): Hanan Jafar, Duaa Abuarqoub, Nidaa Ababneh, Maram Hasan, Shrouq Al-Sotari, Nazneen Aslam, Mohammed Kailani, Mohammed Ammoush, Ziad Shraideh, Abdalla Awidi, Thomas Webster.


Human platelet lysate (hPL) has been considered as the preferred supplement for the xeno-free stem cell culture for many years. However, the biological effect of hPL on the proliferation and differentiation of dental stem cells combined with the use of medical grade synthetic biomaterial is still under investigation. Thus, the optimal scaffold composition, cell type and specific growth conditions, yet need to be formulated. In this study, we aimed to investigate the regenerative potential of dental stem cells seeded on synthetic scaffolds and maintained in osteogenic media supplemented with either hPL or xeno-derived fetal bovine serum (FBS). Two types of dental stem cells were isolated from human impacted third molars and intact teeth; stem cells of apical papilla (SCAP) and periodontal ligament stem cells (PDLSCs). Cells were expanded in cell culture media supplemented with either hPL or FBS. Consequently, proliferative capacity, immunophenotypic characteristics and multilineage differentiation potential of the derived cells were evaluated on monolayer culture (2D) and on synthetic scaffolds fabricated from poly ’lactic-co-glycolic’ acid (PLGA) (3D). The functionality of the induced cells was examined by measuring the concentration of osteogenic markers ALP, OCN and OPN at different time points. Our results indicate that the isolated dental stem cells showed similar mesenchymal characteristics when cultured on hPL or FBS-containing culture media. Scanning electron microscopy (SEM) and H&E staining revealed the proper adherence of the derived cells on the 3D scaffold cultures. Moreover, the increase in the concentration of osteogenic markers proved that hPL was able to produce functional osteoblasts in both culture conditions (2D and 3D), in a way similar to FBS culture. These results reveal that hPL provides a suitable substitute to the animal-derived serum, for the growth and functionality of both SCAP and PDLSCs. Thus the use of hPL, in combination with PLGA scaffolds, can be useful in future clinical trials for dental regeneration.

Partial Text

The term periodontium refers to the combination of dental tissues that support the teeth and they are developmentally, topographically, and functionally related [1]. Periodontitis-associated tissue loss is the most common cause of tooth loss among adult population in the developing countries [2]. Periodontitis is an infectious and inflammatory disease of the supportive tissues of the teeth, which comprises of gingival, cementum, alveolar bone and periodontal ligament (PDL)[3]. PDL is the connective tissue fiber that runs between alveolar bone and cementum. As the periodontal disease progresses, it degenerates the connective tissue fibers on the periodontal ligament (PDL) along with other tissues, leading to tooth loss. The high prevalence of the periodontal disease and the critical role of the PDL in maintaining the physiological function of the tooth have increased the focus of current research on PDL tissue engineering. Due to the limited regenerative ability of PDL, regeneration of the periodontal apparatus composed of bone, PDL and cementum remains a challenge. Hence, a complete regeneration of the periodontium is still unattainable [4, 5].

In the field of regenerative dentistry, the most motivated aim is to reconstruct a whole tooth along with the surrounding tissues. However, this objective is facing some major challenges such as patient incompatibility, progenitor cells, and the derivation of functional ameloblasts [39, 52]. Therefore, the logical approach is to be able to regenerate a mineralized bioengineered root such as the formation of dentin and cementum which are formed from DPSCs and PDLSCs respectively [12, 47].

We conclude that hPL could be used as an efficient substitute of xenogenic products to augment osteogenic differentiation of PDLSCs and SCAP when seeded in a three-dimensional scaffold fabricated from the biocompatible, biodegradable PLGA material. This combination of cells/scaffold/growth supplement seems to fulfil an ideal triad required in regenerating periodontal defects.