giovedì 1 giugno 2006

Le cellule staminali riparano un cuore infranto?

Per rimediare alle sciocchezze e alle noiose liti da cortile sulle cellule staminali in Italia, riportiamo una notizia interessante dal New Scientist (Heart may be home to its own stem cells, 29 maggio 2006):

A team of US researchers has discovered the “home” of stem cells in the heart, lending credence to the idea that the heart has the capacity to repair itself. The finding raises the possibility that these cardiac stem cells could one day be manipulated to rebuild tissues damaged by heart disease – still the leading cause of death in the US and UK.
Because fully developed heart cells do not divide, experts have believed the organ was unable to regenerate after injury. But, in 2003, researchers at Piero Anversa’s laboratory at New York Medical College in Valhalla, New York, US, discovered stem cells in the hearts of mice, and subsequently humans. However, they still did not know whether these stem cells actually resided in the heart or had merely migrated there from another tissue, such as bone marrow.
So Anversa’s colleague Annarosa Leri began to look for tell-tale “niches” of stem cells in the heart, such as a cluster of undifferentiated cells paired with the requisite “nurse” cells – vital for stem cell growth and development.
Using adult mice as a model, she located cardiac stem cell niches, which were especially abundant in the heart’s atria. She found the stem cells clustered together with more mature heart cells in niches between cardiac muscle cells.
Leri and her colleagues have now removed tiny numbers of cardiac stem cells from people undergoing heart operations, grown them in the lab and then transplanted them into the damaged hearts of rats and mice.
The results are promising, says Leri, and may eventually give better heart-healing results than bone-marrow derived stem cells. “We think that these are the cells that normally provide new heart tissue and will most likely be better suited for repair of diseased hearts,” she says.

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