Katz and mice: heartening news

From: Damien Broderick (d.broderick@english.unimelb.edu.au)
Date: Fri Jan 11 2002 - 05:05:40 MST

This is old-ish [and mindboggling] news, but I can't recall seeing it

US researchers have reported that a strain of mice has the remarkable
capacity to regenerate cardiac tissue (Proc Natl Acad Sci 2001; 98:
9830-35). In 1998, the investigators discovered that MRL (Murphy/
Roths/Large) mice whose ears were punched could close the ear holes without
evidence of scarring. The team, led by Ellen Heber-Katz (The Wistar
Institute, Philadelphia, PA, USA), has now studied the effect of damage to
the myocardium, caused by a cryoprobe. "MRL mice and control mice both
showed clear signs of massive injury within the first few days", explains
Heber-Katz. "However, within 2 months, the C57Bl/6 mouse [control] had vast
scarring in the right ventricle while the MRL mouse had almost
normal-looking heart tissue."

 "This is a lovely study", comments Rosenthal. "The group has published
previously on the remarkable wound-healing capacity of the MRL mouse
strain. They now turn their attention to the hardest of tissues to
heal--the myocardium." The investigators identified the cells in the injury
site of MRL mice as dividing myocytes, whereas control mice had only a
small number of dividing cells. The control mice had increased scar tissue
after injury, but the amount of scar tissue in MRL mice decreased. "We
believe that the MRL mouse has the ability to block scar formation, and
under these circumstances cardiomyocytes can divide", explains Heber-Katz.
"Possibly by blocking or eliminating scar formation other mammals can show
this regenerative response."

 "The application of these findings to human clinical practice is still
some way off--the genes must be identified, and their action
characterised", comments Rosenthal. "Still, the information gained along
the way is likely to enlighten our understanding of the regeneration

7 The Lancet
Volume 358, Issue 9280
11 August 2001
Page 475

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