Due to the controversy of using/harvesting real human embryonic stem cells (hESC), the process during which a human embryo is destroyed, other alternatives have been investigated and utilized in treatment so far. Now scientists from Oregon Health and Science University managed to produced viable hESCs from Adult DNA introduced to a blank egg (without DNA content), hence avoiding the destruction of a potential human being conceived in vivo or in vitro.
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| Stem cell |
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| Mature stromal cell |
The benefit of hESCs is their ability to grow into ANY fully functional tissue type (pluripotency), whereas adult stem cells (SCs), induced SCs and other SCs types can usually mature only in a handful of different adult cell types and often only to some degree (not 100% functional match to the desired tissue type).
The major Added Value of cloned hESCs over non clonal hESCs is the usage of an arbitrary adult DNA, e.g. patients own (hence the clone), and therefore clonal hESCs do not create problems of rejection by patient's immune system.
The main issue of hESCs now remains the great tendency of forming non cancerous tumors /teratomas (e.g. one can grow a tooth bundled with some liver tissues in ones eye). Also some may consider the potential for cloning a human being a problem ^_^
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Harvard scientist identified a protein known as GDF-11, that has rejuvenating effect on hearts of old mice. The old thick heart reverted to more youthful state after exposure to the protein.
After scientists shunt together circulatory systems of an old and young mouse. Later they observed that old thick heart reverted to its younger phenotype. The "culprit" was traced back to the GDF-11 protein.
This finding holds a great potential for treating various heart condition in humans.
Remember all the fairy tales where old evil queen bathed in or drank young virgins' blood, well it was not that far off. Please do not try this at home. GDF-11 will not absorbed through your skin or will be digested/destroyed in your guts and you will get chair.
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A novel technique to grow new teeth was tested on mouse, when human epithelial gum stem cells were mixed with mouse mesenchymal embryonic stem cells.
This mix of the two cell types produces a fully formed tooth.
The next challenge is to find an efficient source of human mesenchymal adult stem cells, right now only 'controversial' embryonic source is available (as claimed in the source article, could be questioned).
[Source]
A post for human mesenchymal stem cells coming up.
The Scripps Research Institute scientists have found a new and very effective way to reprogram a bone marrow stem cell into a Brain Cell Progenitor. Bone marrow stem cells are known to normally mature into white blood cells.
This was achieved by an interaction of a single antibody with a receptor on the marrow cell and
is probably the simplest transdifferentiation technique to date.
[edit 4 Jul 2013 ]
Stem cell induction (creation of induced stem cells iSC) from a differentiated adult cell without altering its DNA is also much safer than inducing a SC by introduction of a foreign DNA piece into its native DNA by e.g. a viral vector. These iSC cell lines are more prone to grow noncancerous tumors. See e.g. here.
Antibody induced transdifferentiation, IMHO, is an extremely promising low 'collateral damage' and elegant technique.
More details for the story are Here.
