RESUMO
BACKGROUND: Bone grafting is the standard treatment for critical bone defects, but autologous grafts have limitations like donor site morbidity and limited availability, while commercial artificial grafts may have poor integration with surrounding bone tissue, leading to delayed healing. Magnesium deficiency negatively impacts angiogenesis and bone repair. Therefore, incorporating magnesium into a synthetic biomaterial could provide an excellent bone substitute. This study aims to evaluate the morphological, mechanical, and biological properties of a calcium phosphate cement (CPC) sponge composed of tetracalcium phosphate (TTCP) and monocalcium phosphate monohydrate (MCPM), which could serve as an excellent bone substitute by incorporating magnesium. METHODS: This study aims to develop biomedical materials composed mainly of TTCP and MCPM powder, magnesium powder, and collagen. The materials were prepared using a wet-stirred mill and freeze-dryer methods. The particle size, composition, and microstructure of the materials were investigated. Finally, the biological properties of these materials, including 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide (MTT) assay for biocompatibility, effects on bone cell differentiation by alkaline phosphatase (ALP) activity assay and tartrate-resistant acid phosphatase (TRAP) activity assay, and endothelial cell tube formation assay for angiogenesis, were evaluated as well. RESULTS: The data showed that the sub-micron CPC powder, composed of TTCP/MCPM in a 3.5:1 ratio, had a setting time shorter than 15 minutes and a compressive strength of 4.39±0.96 MPa. This reveals that the sub-micron CPC powder had an adequate setting time and mechanical strength. We found that the sub-micron CPC sponge containing magnesium had better biocompatibility, including increased proliferation and osteogenic induction effects without cytotoxicity. The CPC sponge containing magnesium also promoted angiogenesis. CONCLUSION: In summary, we introduced a novel CPC sponge, which had a similar property to human bone promoted the biological functions of bone cells, and could serve as a promising material used in bone regeneration for critical bone defects.
RESUMO
Extracellular communication, in other words, crosstalk between cells, has a pivotal role in the survival of an organism. This communication occurs by different methods, one of which is extracellular vesicles. Exosomes, which are small lipid extracellular vesicles, have recently been discovered to have a role in signal transduction between cells inside the body. These vesicles contain important bioactive molecules including lipids, proteins, DNA, mRNA, and noncoding RNAs such as microRNAs (miRNAs). Exosomes are secreted by all cells including immune cells (macrophages, lymphocytes, granulocytes, dendritic cells, mast cells) and tumor cells. The tumor microenvironment (TME) represents a complex network that supports the growth of tumor cells. This microenvironment encompasses tumor cells themselves, the extracellular matrix, fibroblasts, endothelial cells, blood vessels, immune cells, and non-cellular components such as exosomes and cytokines. This review aims to provide insights into the latest discoveries concerning how the immune system communicates internally and with other cell types, with a specific focus on research involving exosomal miRNAs in macrophages, dendritic cells, B lymphocytes, and T lymphocytes. Additionally, we will explore the role of exosomal miRNA in the TME and the immunomodulatory effect.