29 May 2008

Bones from stem cells: a new achievement

Until now, researchers' attempts to stimulate the formation of bone tissue from adult human stem cells, for example, to repair bone damage, have failed. Dutch scientists at the University of Twente, working under the guidance of Dr. Jan de Boer, have demonstrated that the activation of the protein kinase A enzyme (PKA) in stem cells before their implantation contributes to the formation of bone tissue.

In animal experiments, adult mesenchymal stem cells have already been used successfully enough to restore bones. Attempts to do the same with adult human stem cells (for example, bone marrow cells) have so far been less successful. The authors claim that the activation of protein kinase A stimulates cell maturation already in the laboratory. When such cells are applied to a special carrier and implanted into a mouse, an almost complete bone is formed.

The enzyme protein kinase A performs many functions in the cell. Signaling molecules of cyclic adenosine monophosphate (cAMP) activate protein kinase A, which, according to the authors, triggers mutual stimulation of stem cells. The addition of cAMP to the culture of mesenchymal stem cells stimulates not only their maturation, but also the secretion of various compounds by cells that stimulate bone growth.

The advantage of pre-stimulation of bone cell formation is due to the possibility of removing the stimulus immediately before implantation. Until now, when conducting such experiments, researchers have used high concentrations of a hormone that stimulates bone growth, which was injected into a carrier or a frame covered with stem cells. The new approach makes it possible to significantly reduce the concentration of hormones used and bring it as close as possible to the natural one.

The article "cAMP/PKA pathway activation in human mesenchymal stem cells in vitro results in robust bone formation in vivo" was published on May 20 in the on-line version of Proceedings of the National Academy of Sciences of the USA.

Portal "Eternal youth" www.vechnayamolodost.ru based on the materials of ScienceDaily


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