WIKIMEDIA, NISSIM BENVENISTYThe existence of very small embryonic-like stem cells (VSELs) has been hotly debated by scientists since they were first reported in mouse bone marrow in 2005. The cells were later identified in human blood and bone marrow as well, and have been proposed as a viable alternative to mouse and human embryonic stem cells (ESCs) in research and medicine. But a study published today (July 24) in Stem Cell Reports has called the very existence of VSELs in question, with the senior author deeming them a “distraction.”
“The results cast strong doubt on the existence of pluripotent VSELs in the bone marrow,” said Martin Pera, chair of Stem Cell Sciences at the University of Melbourne in Australia, who was not involved in the study. “Many previous reports claiming to identify pluripotent stem cells in adult tissues have similarly failed to stand up to careful scrutiny.”
Mariusz Ratajczak, director of the Developmental Biology Research Program at the University of Louisville, is widely credited as the discoverer of VSELs. He has claimed to isolate VSELs from mouse and human tissues, estimating them to be 3–5 micrometers in size and noting that they express pluripotent marker genes. Ratajczak has suggested that VSELs may possess embryonic-stem-cell-like qualities and has argued that finding such cells in an ...
