How many daughter cells are created in the cell cycle?

Stem cells created (cloned) from adult cells for the first time

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Stem

A quality sword requires toughness on the inside and hardness on the outside. That way it can keep a sharp edge yet bend instead of shatter. Getting these properties requires blanking the metal back to a virgin state, adding the right molecular alloying ingredients, and then controlling the rate of the natural processes that occur as its final structure crystallizes out. Using that general method, researchers have just succeeded in returning adult somatic (body) cells to a virgin stem cell state which can then be made into nearly any tissue.

The key word here is "adult." Last year, researchers from Oregon perfected a process to therapeutically clone human embryos. Basically that means producing cells that are genetically identical to a donor for the purpose of treating disease. We described the critical details of the technique, known as somatic-cell nuclear transfer, in an earlier post. In a nutshell, the nucleus from the cell to be "cloned" is fused with an egg that has its own nucleus removed. Caffeine is used to stall various autonomous developmental programs during a fusion process that has been initiated with an electric pulse. The new hybrid cell that results has full "stem cell" character which can be biased into different forms by adding various instructor molecules to the mix.

Dolly

The new results, as we mentioned, were achieved with somatic cells from two men [DOI: 10.1016/j.stem.2014.03.015]. This is important because it is generally adults who stand to benefit the most from a fresh supply of cells to revitalize their ailing organs. In smithing a sword, the desired crystal structure is achieved by controlling the amount of time spent in different phases of cooling. Often there is more than one heating stage as the metal is first slowly tempered through one regime, than recycled back for a second tortured phase with a quicker quench. As for swords, the key element for getting the adult cells to work was to extend a critical delay phase — in this case that around the time the cells were electrically fused. This tempering period is a time for the cell to reorganize prior to committing itself to cell division. After many painstaking experiments, it was found that the 30-minute delay used for the embryonic cell fusions needed to be extended to two hours for the adult cells.

An alternative method for creating stem cells was recently presented which used acid and mechanical persuasion to beat normal cells back into the pluripotent form. This method has been difficult to replicate, and as a result of the controversy surrounding the affair the study has been retracted. That's not to say that this shortcut is off the table though. Researchers continue to look for better ways to produce stem cells with more creative power, from cells that are ever further set in their ways. The new studies reported here were able to use dermal fibroblasts, essentially skin cells, from both a 35-year-old and 75-year-old man. Previously skin cells have been turned into other kinds of cells, particularly neurons. Now they can become any kind of cell. (Read: Regenerated human heart tissue beats on its own, leads towards replacement hearts and other organs.)

In a sense all cells are like playdough. The longer they have been held in any one sculpted form, the more dried-out and difficult to revert to a multipotent state they become. The same inflexibility still persists as a social mindset of fear in many countries that do not permit federal funding of this kind of research (this new work was funded in South Korea with some participation from US scientists). As researchers begin to learn new tricks to re-infuse cells with moisturizing chemical and mechanical regimens, we all have much to gain. If we are going to be benefactors of this technology, it seems that we should also be producers of it.