Propagation of Stromal Cells in Heparinized pHPL Medium

Pooled HPL (pHPL) was produced as described previously^{15 ,53 (link)} and was used to supplement alpha modified Minimum Essentials Eagle’s Medium (α-MEM, Sigma Aldrich, St. Louis, MO, USA) (10% v/v) for propagation of stromal cells. Three different medium types were generated: (1) pHPL supplemented α-MEM with heparin (2 IU/ml; Biochrom, Berlin, Germany) to avoid clot formation (+fibrinogen/+heparin), (2) pHPL supplemented α-MEM prepared by mechanical fibrinogen-depletion as described previously^{33 (link)} (−fibrinogen/−heparin) and (3) pHPL supplemented, mechanically fibrinogen-depleted α-MEM with heparin (−fibrinogen/+heparin). After addition of 5.5 mM (N2)-L-Alanyl-L-Glutamin (Dipeptiven, Fresenius Kabi, Graz, Austria) all media were sterile filtrated before use.