Objective(s): Autologous bone transplantation known as the “ gold standard” to reconstruction of osseous defects has known disadvantages. This study was designed to explore the effects of hydroxy-apatite/tricalcium-phosphate (HA/TCP) and platelet-rich plasma (PRP) on the osteogenesis ability of human adipose-derived mesenchymal stem cells (HADMSCS) in vitro and in vivo. Materials and Methods: HADMSCS were incubated with HA/TCP granules and/or PRP in vitro and then, cell proliferation and differentiation was assessed by MTT assay, AZR S staining and SEM examination. In vivo, four cylindrical defects were drilled in the mandibular bones of 5 mongrel dogs and divided randomly into the following groups: I-autologous crushed bone, II-no filling material, III-HA/TCP and PRP, IV-PRP-enriched HADMSCS seeded on HA/TCP granules. Inserted HADMSCS were labeled to trace their contribution to bone tissue regeneration. Finally, cell tracing and tissue regeneration were evaluated by immunohistochemistry and histomorphometry methods, respectively. Results: In vitro, co-incubation with HA/TCP granules significantly reduced proliferation and osteogenic differentiation ability of HADMSCS; while PRP application promoted these capacities (P<0. 05). In vivo, PRP-enriched HADMSCS seeded on HA/TCP granules induced considerable bone formation in osseous defects (P<0. 05). It was obviously shown that HADMSCS were incorporated into the newly-formed bone. Conclusion: Based on this study, application of stem cells could offer a helpful therapeutic tool in bone tissue regeneration. Although inserted HADMSCS were identifiable throughout the newly-formed bone tissue, their few number could be an indicator of indirect role of HADMSCS in tissue regeneration.

Objective: Neuroblastoma (NB) is one of the frequently observed malignant solid tumors of childhood and infancy, accounting for 15% of pediatric cancer deaths. Recently, the approach of differentiation therapy has shown considerable promise in effective treatment of NB patients. MiR-124 belongs to the nervous system-specific miRNAs that is increased during neuronal differentiation and may be one of the potential therapeutic targets for the treatment of NB. However, despite its well-established therapeutic potential, its efficient delivery to the targeted tumor cells is a challenging task. Mesenchymal stem cells (MSCs) are multipotent adult progenitor cells that have antitumor properties, and they can migrate to cancer cells and tumors. This study aimed to assess whether human adipose tissue-derived MSCs (HADMSCS) have the potential to deliver exogenous miRNAs to NB cells to induce differentiation and decrease proliferation of cancer cells. Materials and Methods: In this experimental study, hAD-MSCs were isolated, cultured, and differentiated. The M17 human NB cell line were also cultured. A specific type of miRNAs, i. e., miR-124 was successfully delivered to M17 NB cells with the aid of hAD-MSCs using the direct or indirect (exosome-based) contacts. Results: It was shown that indirect delivery of miR-124 considerably decreased the proliferation of NB cells and induced their differentiation. Conclusion: The results suggest the use of delivered exogenous miRNAs by the derived exosomes from hAD-MSCs as a novel cell-free stem cell-based therapy for NB cancer.