The Impact of Nano-Hydroxyapatite Scaffold Enrichment on Bone Regeneration In Vivo-A Systematic Review.

OBJECTIVES: In order to ensure improved and accelerated bone regeneration, nano-hydroxyapatite scaffolds are often enriched with different bioactive components to further accelerate and improve bone healing. In this review, we critically examined whether the enrichment of nHAp/polymer scaffolds with growth factors, hormones, polypeptides, microRNAs and exosomes improved new bone formation in vivo. MATERIALS AND METHODS: Out of 2989 articles obtained from the literature search, 106 papers were read in full, and only 12 articles met the inclusion criteria for this review. RESULTS: Several bioactive components were reported to stimulate accelerated bone regeneration in a variety of bone defect models, showing better results than bone grafting with nHAp scaffolds alone. CONCLUSIONS: The results indicated that composite materials based on nHAp are excellent candidates as bone substitutes, while nHAp scaffold enrichment further accelerates bone regeneration. The standardization of animal models should be provided in order to clearly define the most significant parameters of in vivo studies. Only in this way can the adequate comparison of findings from different in vivo studies be possible, further advancing our knowledge on bone regeneration and enabling its translation to clinical settings.

Anti-Cancer Activities of Nano Amorphous Calcium Phosphates toward Premalignant and Oral Cancer Cells.

Despite advancements in treatment, the squamous cell carcinoma (OSCC) patient survival rate remains stagnant. Conventional therapies have limited effectiveness, necessitating novel agents. Our study aims to synthesize and characterize amorphous calcium phosphate nanoparticles (nACPs), assess their potential cytotoxic effects on premalignant and malignant OSCC cells, and investigate possible mechanisms of action. The morphological features of nACP were investigated by field emission scanning coupled with energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), and particle size distribution (PSD). Then, we examined the effect of nACPs on nanoparticle uptake, cell adhesion, viability, invasion ability, cell cycle, and gene expression. nACP uptake was dose-dependent, induced limited selectivity in cytotoxicity between healthy and malignant cells, and affected cellular adhesion and invasion. Early apoptosis was the predominant type of cell death. The nACP effect on viability was verified by alterations in the genes associated with apoptosis and proliferation. A high concentration of nACP was shown to arrest the cell cycle progression in the G0/G1 phase of both malignant and premalignant cells. This type of nACP justifies the development of a strategy for its potential use as an anti-cancer agent and/or anti-cancer active carrier for various drugs in oral cancer treatments.

Osteogenic and Adipogenic Differentiation Potential of Oral Cancer Stem Cells May Offer New Treatment Modalities.

(1) Treatment failure of oral squamous cell carcinoma (OSCC) is generally due to the development of therapeutic resistance caused by the existence of cancer stem cells (CSCs), a small cell subpopulation with marked self-renewal and differentiation capacity. Micro RNAs, notably miRNA-21, appear to play an important role in OSCC carcinogenesis. Our objectives were to explore the multipotency of oral CSCs by estimating their differentiation capacity and assessing the effects of differentiation on stemness, apoptosis, and several miRNAs' expression. (2) A commercially available OSCC cell line (SCC25) and five primary OSCC cultures generated from tumor tissues obtained from five OSCC patients were used in the experiments. Cells harboring CD44, a CSC marker, were magnetically separated from the heterogeneous tumor cell populations. The CD44+ cells were then subjected to osteogenic and adipogenic induction, and the specific staining was used for differentiation confirmation. The kinetics of the differentiation process was evaluated by qPCR analysis of osteogenic (Bone Morphogenetic Protein-BMP4, Runt-related Transcription Factor 2-RUNX2, Alkaline Phosphatase-ALP) and adipogenic (Fibroblast Activation Protein Alpha-FAP, LIPIN, Peroxisome Proliferator-activated Receptor Gamma-PPARG) markers on days 0, 7, 14, and 21. Embryonic markers (Octamer-binding Transcription Factor 4-OCT4, Sex Determining Region Y Box 2-SOX2, and NANOG) and micro RNAs (miRNA-21, miRNA-133, and miRNA-491) were also correspondingly evaluated by qPCR. An Annexin V assay was used to assess the potential cytotoxic effects of the differentiation process. (3) Following differentiation, the levels of markers for the osteo/adipo lineages showed a gradual increase from day 0 to day 21 in the CD44+ cultures, while stemness markers and cell viability decreased. The oncogenic miRNA-21 also followed the same pattern of gradual decrease along the differentiation process, while tumor suppressor miRNA-133 and miRNA-491 levels increased. (4) Following induction, the CSCs acquired the characteristics of the differentiated cells. This was accompanied by loss of stemness properties, a decrease of the oncogenic and concomitant, and an increase of tumor suppressor micro RNAs.

Acetylsalicylic-acid (ASA) regulation of osteo/odontogenic differentiation and proliferation of human dental pulp stem cells (DPSCs) in vitro.

OBJECTIVE: The study aimed to investigate acetylsalicylic acid (ASA) effects on osteo/odontogenic differentiation and proliferation of dental pulp stem cells (DPSCs) in vitro and the potential involvement of adenosine monophosphate-activated protein kinase (AMPK) pathway in these processes. DESIGN: DPSCs were isolated from third molars pulp tissues of five patients and grown in osteogenic medium alone or supplemented with ASA. Expression of DPSCs markers was tested by flow-cytometry. Cytotoxicity of ASA at concentrations of 10, 50 and 100 µg/ml was tested by MTT and NR assays. Osteo/odontogenic differentiation was analyzed via alizarin red staining and ALP activity. Quantitative PCR (qPCR) was used for osteo/odontogenic markers' (DSPP, BMP2, BMP4, BSP, OCN and RUNX2) and c-Myc expression analysis. AMPK inhibition of ASA-induced osteo/odontogenesis was tested by qPCR of selected markers (DSPP, OCN and RUNX2). RESULTS: Cytotoxicity assays showed that only the highest ASA dose decreased cell viability (89.1 %). The smallest concentration of ASA applied on DPSCs resulted in a remarkable enhancement of osteo/odontogenic differentiation, as judged by increased mineralized nodules' formation, ALP activity and gene expression of analyzed markers (increase between 2 and 30 folds), compared to untreated cells. ASA also increased DPSCs proliferation. Interestingly, AMPK inhibition per se upregulated DSPP, OCN and RUNX2; the gene upregulation was higher when ASA treatment was also included. c-Myc expression level decreased in cultures treated with ASA, indicating undergoing differentiation processes. CONCLUSIONS: Low concentrations of ASA (corresponding to the standard use in cardiovascular patients), were shown to stimulate osteo/odontogenic differentiation of dental pulp stem cells.