1 Musculoskeletal Research Center Berlin, Charite - Universitatsmedizin , Berlin, Germany ; Berlin-Brandenburg Center for Regenerative Therapies, Charite - Universitatsmedizin , Berlin, Germany.
2 Free University Berlin, Department of Biology, Chemistry, Pharmacy , Berlin, Germany ; Musculoskeletal Research Center Berlin, Charite - Universitatsmedizin , Berlin, Germany.
3 Musculoskeletal Research Center Berlin, Charite - Universitatsmedizin , Berlin, Germany.