In cell therapy, stem cells are commonly used to repair damages and treat injuries. Since 2001, adipose-derived stem cells (ASC) have been known to be found in adipose tissue, as well. It consists of adipocytes, which make up a third of the cells, and a stromal vascular fraction (SVF), which also comprises ASC.
They are used for healing of wounds, chronic ulcers and fistulas, in cosmetic surgery and for treating radiation injuries. Currently, ASC are routinely obtained from SVF by a minimally invasive process of subcutaneous lipoaspiration, followed by enzymatic processing with collagenase. The process is problematic due to enzyme residues, which are detrimental to skin and tissue regeneration. Additionally, the use of enzymes is strictly regulated. Therefore mechanical methods as alternatives are studied with centrifugation being the most rudimentary.
In this thesis, the effectiveness of mechanical isolation of SVF from human adipose tissue as an alternative to the centrifugation method was studied. We tested how the isolation efficiency is affected by the shape of a connecting nozzle and the number of transfers through the syringe. We compared two nozzles of different shapes with 15, 30 and 60 transfers. In the control experiment, only centrifugation was used.
The efficiency of the procedure was assessed by analysing the parameters of the obtained cells. The number of the cells and their clonogenic potential were determined. Subsequently, the ability of the cells to differentiate was measured by culturing them in adipoinduction and osteoinduction medium. Their differentiation in the adipoinduction medium was evaluated by Oil Red O, which dyes lipid vacuoles. Their differentiation in the osteoinduction medium was determined by measuring the concentration of calcium, which had been excreted by the cells.
We found that the mechanical isolation process can be optimised. Compared to centrifugation, a 93 times higher efficiency was measured. However, the enzymatic degradation method was still 16 times more efficient that the optimised mechanical decomposition. The cells obtained by the optimised mechanical process exhibited slightly poorer phenotypic properties, yet they had the same differentiation ability as the enzymatically isolated cells.
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