PURIFICATION OF HUMAN MUSCLE SATELLITE CELLS BY FLOW-CYTOMETRY

To purify satellite cells directly from human muscle biopsies, we have developed a method based on size separation of dissociated cells by f low cytometry. Immediately after tryptic dissociation of human muscle biopsies and elimination of erythrocytes, microscopic observation and flow cytometry analysis of cell suspensions revealed two populations o f cells differing in size and nucleocytoplasmic ratio. Clonal cultures of these two cell types with a manual procedure demonstrated that onl y the small cells were myogenic satellite cells. Flow cytometry-sortin g and analysis of the small cell population showed that (1) all sorted cells contained desmin immediately after dissociation and plating; (2 ) more than 98% of the cells expressed the 5.1.H11 epitope after 2 wee ks of proliferation in culture; and (3) 90% of the sorted cells were a ble to form myotubes when cultivated at low density or in clonal cultu res. Thus, human muscle satellite cells can be directly purified from human muscle samples using flow cytometry.