Objective: Allogeneic mesenchymal stromal cells (MSCs) are used in the 1-stage treatment of articular cartilage defects. The aim of this study is to investigate whether transport of mitochondria... Show moreObjective: Allogeneic mesenchymal stromal cells (MSCs) are used in the 1-stage treatment of articular cartilage defects. The aim of this study is to investigate whether transport of mitochondria exists between chondrocytes and MSCs and to investigate whether the transfer of mitochondria to chondrocytes contributes to the mechanism of action of MSCs. Design: Chondrocytes and MSCs were stained with MitoTracker, and CellTrace was used to distinguish between cell types. The uptake of fluorescent mitochondria was measured in cocultures using flow cytometry. Transport was visualized using fluorescence microscopy. Microvesicles were isolated and the presence of mitochondria was assessed. Mitochondria were isolated from MSCs and transferred to chondrocytes using MitoCeption. Pellets of chondrocytes, chondrocytes with transferred MSC mitochondria, and cocultures were cultured for 28 days. DNA content and proteoglycan content were measured. Mitochondrial DNA of cultured pellets and of repair cartilage tissue was quantified. Results: Mitochondrial transfer occurred bidirectionally within the first 4 hours until 16 hours of coculture. Transport took place via tunneling nanotubes, direct cell-cell contact, and extracellular vesicles. After 28 days of pellet culture, DNA content and proteoglycan deposition were higher in chondrocyte pellets to which MSC mitochondria were transferred than the control groups. No donor mitochondrial DNA was traceable in the biopsies, whereas an increase in MSC mitochondrial DNA was seen in the pellets. Conclusions: These results suggest that mitochondrial transport plays a role in the chondroinductive effect of MSCs on chondrocytes in vitro. However, in vivo no transferred mitochondria could be traced back after 1 year. Show less
Articular cartilage is a connective tissue structure that is found in anatomical areas that are important for the movement of the human body. Osteoarthritis is the ailment that most often affects... Show moreArticular cartilage is a connective tissue structure that is found in anatomical areas that are important for the movement of the human body. Osteoarthritis is the ailment that most often affects the articular cartilage. Due to its poor intrinsic healing capacity, damage to the articular cartilage is highly detrimental and at present the reconstructive options for its repair are limited. Tissue engineering and the science of nanobiomaterials are two lines of research that together can contribute to the restoration of damaged tissue. The science of nanobiomaterials focuses on the development of different nanoscale structures that can be used as carriers of drugs / cells to treat and repair damaged tissues such as articular cartilage. This review article is an overview of the composition of articular cartilage, the causes and treatments of osteoarthritis, with a special emphasis on nanomaterials as carriers of drugs and cells, which reduce inflammation, promote the activation of biochemical factors and ultimately contribute to the total restoration of articular cartilage. Show less
