Adipogenic differentiation of sub-populations after > 8 pds. Adipogenic differentiation was induced using adipogenic induction medium, control cells were cultured in MSC growth medium (MSCGM). Three weeks after induction gene expression of the adipogenic markers, the transcription factor peroxisome proliferator-activated receptor γ 2 (PPARγ2) and adiponectin was analyzed. Expression relative to GAPDH is presented for each individual culture (left). In parallel, lipid droplets were visualized by Oil Red O staining (bars = 200 μm). Representative pictures of one culture after induction are shown. Only very sporadically were positive cells found (pictures with higher magnification on the right). None of the control cultures was positive. *: significant difference (p < 0.05) between all control cultures compared to all cultures under induction conditions. (For mean expression values see Additional file 1: Table S5).