From Sperm to Heart...well kind of...

Göttingen, Germany -

Pluripotent stem cells derived from primordial germ cells have been previously described. What is more exciting is the possibility of using adult testicular cells as a source of pluripotent stem cells. This was actually published in Nature last year (Guan et al. Pluripotency of spermatogonial stem cells from adult mouse testis. Nature. 2006 Apr 27;440(7088):1199-203). However, the promise of individual specific totipotent stem cells is tempered by the question if they can actually be induced to differentiate into functional tissue.

In a recent paper (Guan et al. Generation of functional cardiomyocytes from adult mouse spermatogonial stem cells. Circ Res. 2007 Jun 8;100(11):1615-25) this type of stem cell was assessed for ability to differentiate into cardiomyocytes.

Researchers used the hanging drop method to differentiate murine primordial germ stem cells into cardiomyocytes and analyzed their functional properties. They found:

a) Differentiation efficiency of beating cardiomyocytes from germinal sources was similar to that from embryonic stem cells.

b) The germinal-derived cardiomyocytes expressed cardiac-specific L-type Ca(2+) channels and responded to Ca(2+) channel-modulating drugs.

c) In a manner similar to normal cardiac cells, the connexin Cx43 was expressed at cell-to-cell contacts in cardiac clusters. Furthermore the gap junctions were functioning as in normal myocardium.

d) When the cardiomyocytes generated from the germinal stem cells were implanted surgically into mouse hearts, they did not cause arrhythmias nor tumors.