gms | German Medical Science

Objectives: Traditionally mesenchymal stem/stromal cells (MSCs) for bone tissue regeneration are obtained from bone marrow aspirates. However, the amount of bone marrow aspirate that can be obtained from one patient is strictly limited in order to reduce adverse effects. A possible alternative may be MSCs derived from fat tissue (Ad-MSCs). Ad-MSCs can typically be obtained in larger amounts with reduced safety concerns for the patients. Thus, these cells represent an interesting option for bone tissue engineering, although their osteogenic differentiation potential is often critically discussed. There are reports that donor age, weight and gender might affect the proliferation and osteogenic differentiation of MSCs, which needs to be taken into consideration when obtaining autologous cells. Up to now little is known whether the location of the fat tissue does affect the proliferation and osteogenic differentiation of the isolated Ad-MSCs.

Methods: Human Ad-MSCs were isolated from subcutaneous fat tissue of different locations, e.g. abdomen, hip, thigh, knee and extremities, by collagenase digestion (ethical vote 385/2012BO2). After expansion the cells were osteogenically differentiated for 14 days (DMEM, 1% FCS, 200 µM L-ascorbic acid-2-phosphate, 5 mM b-glycerol-phosphate, 25 mM HEPES, 1.5 mM CaCl2, 5 µM cholecalciferol). Both proliferation (increase in total protein content) and osteogenic characteristics (AP activity and matrix mineralization) were compared. Data sets were compared by Kruskall Wallis test followed by Dunn's multiple comparison test.

Results and conclusion: Our data show significant differences in proliferation and osteogenic differentiation of Ad-MSCs obtained from subcutaneous fat tissue of different locations. Ad-MSCs obtained from fat tissue of the extremities, the abdomen and the knee showed strong proliferation in spite of the osteogenic stimuli. Increase in AP activity and matrix mineralization; however, were more pronounced in the less proliferative Ad-MSCs from the hip and thigh. Ad-MSCs from the abdomen also showed a measurable increase in osteogenic characteristics. Interestingly, the observed differences were not dependent on donor age, weight or gender. Our data clearly show that the location of the fat tissue affects the proliferation and osteogenic differentiation of the obtained Ad-MSCs. Thus, the choice of fat tissue for isolating Ad-MSCs for bone tissue regeneration might be adapted depending on the required cell amount and purpose.