Tumors form in hearts injected with undifferentiated ES cells (top) but not when ES cells are predifferentiated (bottom).

Tissue regeneration without tumor formation may soon be within reach, at least for heart repair. On page 405, Behfar et al. report that embryonic stem (ES) cells preprogrammed to mature into cardiomyocytes can fix injured hearts in vivo without seeding tumors.

Directing ES cells to become a particular tissue type in vivo is an inefficient process. Consequently, transplanted ES cell populations may give rise to tumors in recipient hosts. Behfar et al. reasoned that delivery of partially differentiated ES cells may result in safe outcome provided that a modulator of differentiation shuts down troublesome tumor pathways.

When ES cells are delivered in vivo, their tumorigenicity is reduced in mice that suffer heart attacks. This is associated with TNF production. But TNF had not been tested for...

The Rockefeller University Press
2007
The Rockefeller University Press
2007
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